Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Methods](https://developer.android.com/reference/java/lang/invoke/VarHandle#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/lang/invoke/VarHandle#inhmethods)
# VarHandle
`
public
abstract
class
VarHandle
`
`
extends https://developer.android.com/reference/java/lang/Object
`
`
`
|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | java.lang.invoke.VarHandle |
*** ** * ** ***
A VarHandle is a dynamically strongly typed reference to a variable, or to a
parametrically-defined family of variables, including static fields,
non-static fields, array elements, or components of an off-heap data
structure. Access to such variables is supported under various
*access modes*, including plain read/write access, volatile
read/write access, and compare-and-set.
VarHandles are immutable and have no visible state. VarHandles cannot be
subclassed by the user.
A VarHandle has:
- a `https://developer.android.com/reference/java/lang/invoke/VarHandle#varType()` T, the type of every variable referenced by this VarHandle; and
- a list of `https://developer.android.com/reference/java/lang/invoke/VarHandle#coordinateTypes()` `CT1, CT2, ..., CTn`, the types of *coordinate expressions* that jointly locate a variable referenced by this VarHandle.
Variable and coordinate types may be primitive or reference, and are represented by `Class` objects. The list of coordinate types may be empty.
Factory methods that produce or `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup` VarHandle instances document the supported variable type and the list
of coordinate types.
Each access mode is associated with one *access mode method* , a
[signature polymorphic](https://developer.android.com/reference/java/lang/invoke/MethodHandle#sigpoly) method named
for the access mode. When an access mode method is invoked on a VarHandle
instance, the initial arguments to the invocation are coordinate expressions
that indicate in precisely which object the variable is to be accessed.
Trailing arguments to the invocation represent values of importance to the
access mode. For example, the various compare-and-set or compare-and-exchange
access modes require two trailing arguments for the variable's expected value
and new value.
The arity and types of arguments to the invocation of an access mode
method are not checked statically. Instead, each access mode method
specifies an `https://developer.android.com/reference/java/lang/invoke/VarHandle#accessModeType(java.lang.invoke.VarHandle.AccessMode)`,
represented as an instance of `https://developer.android.com/reference/java/lang/invoke/MethodType`, that serves as a kind of
method signature against which the arguments are checked dynamically. An
access mode type gives formal parameter types in terms of the coordinate
types of a VarHandle instance and the types for values of importance to the
access mode. An access mode type also gives a return type, often in terms of
the variable type of a VarHandle instance. When an access mode method is
invoked on a VarHandle instance, the symbolic type descriptor at the
call site, the run time types of arguments to the invocation, and the run
time type of the return value, must [match](https://developer.android.com/reference/java/lang/invoke/VarHandle#invoke) the types
given in the access mode type. A runtime exception will be thrown if the
match fails.
For example, the access mode method `https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndSet(java.lang.Object[])` specifies that if
its receiver is a VarHandle instance with coordinate types
`CT1, ..., CTn` and variable type `T`, then its access mode type
is `(CT1 c1, ..., CTn cn, T expectedValue, T newValue)boolean`.
Suppose that a VarHandle instance can access array elements, and that its
coordinate types are `String[]` and `int` while its variable type
is `String`. The access mode type for `compareAndSet` on this
VarHandle instance would be
`(String[] c1, int c2, String expectedValue, String newValue)boolean`.
Such a VarHandle instance may be produced by the
`https://developer.android.com/reference/java/lang/invoke/MethodHandles#arrayElementVarHandle(java.lang.Class)` and
access array elements as follows:
String[] sa = ...
VarHandle avh = MethodHandles.arrayElementVarHandle(String[].class);
boolean r = avh.compareAndSet(sa, 10, "expected", "new");
Access modes control atomicity and consistency properties.
*Plain* read (`get`) and write (`set`)
accesses are guaranteed to be bitwise atomic only for references
and for primitive values of at most 32 bits, and impose no observable
ordering constraints with respect to threads other than the
executing thread. *Opaque* operations are bitwise atomic and
coherently ordered with respect to accesses to the same variable.
In addition to obeying Opaque properties, *Acquire* mode
reads and their subsequent accesses are ordered after matching
*Release* mode writes and their previous accesses. In
addition to obeying Acquire and Release properties, all
*Volatile* operations are totally ordered with respect to
each other.
Access modes are grouped into the following categories:
- read access modes that get the value of a variable under specified memory ordering effects. The set of corresponding access mode methods belonging to this group consists of the methods `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getOpaque(java.lang.Object[])`.
- write access modes that set the value of a variable under specified memory ordering effects. The set of corresponding access mode methods belonging to this group consists of the methods `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#setOpaque(java.lang.Object[])`.
- atomic update access modes that, for example, atomically compare and set the value of a variable under specified memory ordering effects. The set of corresponding access mode methods belonging to this group consists of the methods `https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndSet(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSetPlain(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSet(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSetAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSetRelease(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndExchangeAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndExchange(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndExchangeRelease(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndSet(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndSetAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndSetRelease(java.lang.Object[])`.
- numeric atomic update access modes that, for example, atomically get and set with addition the value of a variable under specified memory ordering effects. The set of corresponding access mode methods belonging to this group consists of the methods `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndAdd(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndAddAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndAddRelease(java.lang.Object[])`,
- bitwise atomic update access modes that, for example, atomically get and bitwise OR the value of a variable under specified memory ordering effects. The set of corresponding access mode methods belonging to this group consists of the methods `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseOr(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseOrAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseOrRelease(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseAnd(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseAndAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseAndRelease(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseXor(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseXorAcquire(java.lang.Object[])`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseXorRelease(java.lang.Object[])`.
Factory methods that produce or `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup` VarHandle instances document the set of access modes that are
supported, which may also include documenting restrictions based on the
variable type and whether a variable is read-only. If an access mode is not
supported then the corresponding access mode method will on invocation throw
an `UnsupportedOperationException`. Factory methods should document
any additional undeclared exceptions that may be thrown by access mode
methods.
The `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])` access mode is supported for all
VarHandle instances and the corresponding method never throws
`UnsupportedOperationException`.
If a VarHandle references a read-only variable (for example a `final`
field) then write, atomic update, numeric atomic update, and bitwise atomic
update access modes are not supported and corresponding methods throw
`UnsupportedOperationException`.
Read/write access modes (if supported), with the exception of
`get` and `set`, provide atomic access for
reference types and all primitive types.
Unless stated otherwise in the documentation of a factory method, the access
modes `get` and `set` (if supported) provide atomic access for
reference types and all primitives types, with the exception of `long`
and `double` on 32-bit platforms.
Access modes will override any memory ordering effects specified at
the declaration site of a variable. For example, a VarHandle accessing
a field using the `get` access mode will access the field as
specified *by its access mode* even if that field is declared
`volatile`. When mixed access is performed extreme care should be
taken since the Java Memory Model may permit surprising results.
In addition to supporting access to variables under various access modes,
a set of static methods, referred to as memory fence methods, is also
provided for fine-grained control of memory ordering.
The Java Language Specification permits other threads to observe operations
as if they were executed in orders different than are apparent in program
source code, subject to constraints arising, for example, from the use of
locks, `volatile` fields or VarHandles. The static methods,
`https://developer.android.com/reference/java/lang/invoke/VarHandle#fullFence()`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#acquireFence()`,
`https://developer.android.com/reference/java/lang/invoke/VarHandle#releaseFence()`, `https://developer.android.com/reference/java/lang/invoke/VarHandle#loadLoadFence()` and
`https://developer.android.com/reference/java/lang/invoke/VarHandle#storeStoreFence()`, can also be used to impose
constraints. Their specifications, as is the case for certain access modes,
are phrased in terms of the lack of "reorderings" -- observable ordering
effects that might otherwise occur if the fence was not present. More
precise phrasing of the specification of access mode methods and memory fence
methods may accompany future updates of the Java Language Specification.
# Compiling invocation of access mode methods
A Java method call expression naming an access mode method can invoke a VarHandle from Java source code. From the viewpoint of source code, these methods can take any arguments and their polymorphic result (if expressed) can be cast to any return type. Formally this is accomplished by giving the access mode methods variable arity `Object` arguments and `Object` return types (if the return type is polymorphic), but they have an additional quality called *signature polymorphism* which connects this freedom of invocation directly to the JVM execution stack.
As is usual with virtual methods, source-level calls to access mode methods
compile to an `invokevirtual` instruction. More unusually, the
compiler must record the actual argument types, and may not perform method
invocation conversions on the arguments. Instead, it must generate
instructions to push them on the stack according to their own unconverted
types. The VarHandle object itself will be pushed on the stack before the
arguments. The compiler then generates an `invokevirtual` instruction
that invokes the access mode method with a symbolic type descriptor which
describes the argument and return types.
To issue a complete symbolic type descriptor, the compiler must also
determine the return type (if polymorphic). This is based on a cast on the
method invocation expression, if there is one, or else `Object` if the
invocation is an expression, or else `void` if the invocation is a
statement. The cast may be to a primitive type (but not `void`).
As a corner case, an uncasted `null` argument is given a symbolic type
descriptor of `java.lang.Void`. The ambiguity with the type
`Void` is harmless, since there are no references of type `Void`
except the null reference.
# Performing invocation of access mode methods
The first time an `invokevirtual` instruction is executed it is linked by symbolically resolving the names in the instruction and verifying that the method call is statically legal. This also holds for calls to access mode methods. In this case, the symbolic type descriptor emitted by the compiler is checked for correct syntax, and names it contains are resolved. Thus, an `invokevirtual` instruction which invokes an access mode method will always link, as long as the symbolic type descriptor is syntactically well-formed and the types exist.
When the `invokevirtual` is executed after linking, the receiving
VarHandle's access mode type is first checked by the JVM to ensure that it
matches the symbolic type descriptor. If the type
match fails, it means that the access mode method which the caller is
invoking is not present on the individual VarHandle being invoked.
Invocation of an access mode method behaves as if an invocation of
`https://developer.android.com/reference/java/lang/invoke/MethodHandle#invoke(java.lang.Object[])`, where the receiving method handle accepts the
VarHandle instance as the leading argument. More specifically, the
following, where `{access-mode}` corresponds to the access mode method
name:
VarHandle vh = ..
R r = (R) vh.{access-mode}(p1, p2, ..., pN);
behaves as if:
VarHandle vh = ..
VarHandle.AccessMode am = VarHandle.AccessMode.valueFromMethodName("{access-mode}");
MethodHandle mh = MethodHandles.varHandleExactInvoker(
am,
vh.accessModeType(am));
R r = (R) mh.invoke(vh, p1, p2, ..., pN)
(modulo access mode methods do not declare throwing of `Throwable`). This is equivalent to:
MethodHandle mh = MethodHandles.lookup().findVirtual(
VarHandle.class,
"{access-mode}",
MethodType.methodType(R, p1, p2, ..., pN));
R r = (R) mh.invokeExact(vh, p1, p2, ..., pN)
where the desired method type is the symbolic type descriptor and a `https://developer.android.com/reference/java/lang/invoke/MethodHandle#invokeExact(java.lang.Object[])` is performed, since before invocation of the target, the handle will apply reference casts as necessary and box, unbox, or widen primitive values, as if by `https://developer.android.com/reference/java/lang/invoke/MethodHandle#asType(java.lang.invoke.MethodType)` (see also `https://developer.android.com/reference/java/lang/invoke/MethodHandles#varHandleInvoker(java.lang.invoke.VarHandle.AccessMode,%20java.lang.invoke.MethodType)`). More concisely, such behaviour is equivalent to:
VarHandle vh = ..
VarHandle.AccessMode am = VarHandle.AccessMode.valueFromMethodName("{access-mode}");
MethodHandle mh = vh.toMethodHandle(am);
R r = (R) mh.invoke(p1, p2, ..., pN)
Where, in this case, the method handle is bound to the VarHandle instance.
# Invocation checking
In typical programs, VarHandle access mode type matching will usually succeed. But if a match fails, the JVM will throw a `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException`.
Thus, an access mode type mismatch which might show up as a linkage error
in a statically typed program can show up as a dynamic
`WrongMethodTypeException` in a program which uses VarHandles.
Because access mode types contain "live" `Class` objects, method type
matching takes into account both type names and class loaders.
Thus, even if a VarHandle `VH` is created in one class loader
`L1` and used in another `L2`, VarHandle access mode method
calls are type-safe, because the caller's symbolic type descriptor, as
resolved in `L2`, is matched against the original callee method's
symbolic type descriptor, as resolved in `L1`. The resolution in
`L1` happens when `VH` is created and its access mode types are
assigned, while the resolution in `L2` happens when the
`invokevirtual` instruction is linked.
Apart from type descriptor checks, a VarHandles's capability to
access it's variables is unrestricted.
If a VarHandle is formed on a non-public variable by a class that has access
to that variable, the resulting VarHandle can be used in any place by any
caller who receives a reference to it.
Unlike with the Core Reflection API, where access is checked every time a
reflective method is invoked, VarHandle access checking is performed
[when the VarHandle is
created](https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup#access).
Thus, VarHandles to non-public variables, or to variables in non-public
classes, should generally be kept secret. They should not be passed to
untrusted code unless their use from the untrusted code would be harmless.
# VarHandle creation
Java code can create a VarHandle that directly accesses any field that is accessible to that code. This is done via a reflective, capability-based API called `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup`. For example, a VarHandle for a non-static field can be obtained from `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup#findVarHandle(java.lang.Class,%20java.lang.String,%20java.lang.Class)`. There is also a conversion method from Core Reflection API objects, `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup#unreflectVarHandle(java.lang.reflect.Field)`.
Access to protected field members is restricted to receivers only of the
accessing class, or one of its subclasses, and the accessing class must in
turn be a subclass (or package sibling) of the protected member's defining
class. If a VarHandle refers to a protected non-static field of a declaring
class outside the current package, the receiver argument will be narrowed to
the type of the accessing class.
# Interoperation between VarHandles and the Core Reflection API
Using factory methods in the `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup` API, any field represented by a Core Reflection API object can be converted to a behaviorally equivalent VarHandle. For example, a reflective `https://developer.android.com/reference/java/lang/reflect/Field` can be converted to a VarHandle using `https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup#unreflectVarHandle(java.lang.reflect.Field)`. The resulting VarHandles generally provide more direct and efficient access to the underlying fields.
As a special case, when the Core Reflection API is used to view the
signature polymorphic access mode methods in this class, they appear as
ordinary non-polymorphic methods. Their reflective appearance, as viewed by
`https://developer.android.com/reference/java/lang/Class#getDeclaredMethod(java.lang.String,%20java.lang.Class[])`,
is unaffected by their special status in this API.
For example, `https://developer.android.com/reference/java/lang/reflect/Method#getModifiers()`
will report exactly those modifier bits required for any similarly
declared method, including in this case `native` and `varargs`
bits.
As with any reflected method, these methods (when reflected) may be invoked
directly via `https://developer.android.com/reference/java/lang/reflect/Method#invoke(java.lang.Object,%20java.lang.Object[])`,
via JNI, or indirectly via
`https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup#unreflect(java.lang.reflect.Method)`.
However, such reflective calls do not result in access mode method
invocations. Such a call, if passed the required argument (a single one, of
type `Object[]`), will ignore the argument and will throw an
`UnsupportedOperationException`.
Since `invokevirtual` instructions can natively invoke VarHandle
access mode methods under any symbolic type descriptor, this reflective view
conflicts with the normal presentation of these methods via bytecodes.
Thus, these native methods, when reflectively viewed by
`Class.getDeclaredMethod`, may be regarded as placeholders only.
In order to obtain an invoker method for a particular access mode type,
use `https://developer.android.com/reference/java/lang/invoke/MethodHandles#varHandleExactInvoker(java.lang.invoke.VarHandle.AccessMode,%20java.lang.invoke.MethodType)` or
`https://developer.android.com/reference/java/lang/invoke/MethodHandles#varHandleInvoker(java.lang.invoke.VarHandle.AccessMode,%20java.lang.invoke.MethodType)`. The
`https://developer.android.com/reference/java/lang/invoke/MethodHandles.Lookup#findVirtual(java.lang.Class,%20java.lang.String,%20java.lang.invoke.MethodType)`
API is also able to return a method handle to call an access mode method for
any specified access mode type and is equivalent in behaviour to
`https://developer.android.com/reference/java/lang/invoke/MethodHandles#varHandleInvoker(java.lang.invoke.VarHandle.AccessMode,%20java.lang.invoke.MethodType)`.
# Interoperation between VarHandles and Java generics
A VarHandle can be obtained for a variable, such as a field, which is declared with Java generic types. As with the Core Reflection API, the VarHandle's variable type will be constructed from the erasure of the source-level type. When a VarHandle access mode method is invoked, the types of its arguments or the return value cast type may be generic types or type instances. If this occurs, the compiler will replace those types by their erasures when it constructs the symbolic type descriptor for the `invokevirtual` instruction.
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/MethodHandle`
- `https://developer.android.com/reference/java/lang/invoke/MethodHandles`
- `https://developer.android.com/reference/java/lang/invoke/MethodType`
## Summary
| ### Public methods ||
|---|---|
| ` final https://developer.android.com/reference/java/lang/invoke/MethodType` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#accessModeType(java.lang.invoke.VarHandle.AccessMode)(https://developer.android.com/reference/java/lang/invoke/VarHandle.AccessMode accessMode) ` Obtains the access mode type for this VarHandle and a given access mode. |
| ` static void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#acquireFence()() ` Ensures that loads before the fence will not be reordered with loads and stores after the fence. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndExchange(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndExchangeAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndExchangeRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final boolean` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#compareAndSet(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/util/List>` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#coordinateTypes()() ` Returns the coordinate types for this VarHandle. |
| ` static void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#fullFence()() ` Ensures that loads and stores before the fence will not be reordered with loads and stores after the fence. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Returns the value of a variable, with memory semantics of reading as if the variable was declared non-`volatile`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Returns the value of a variable, and ensures that subsequent loads and stores are not reordered before this access. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndAdd(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically adds the `value` to the current value of a variable with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`, and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndAddAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically adds the `value` to the current value of a variable with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`, and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndAddRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically adds the `value` to the current value of a variable with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`, and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseAnd(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise AND between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseAndAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise AND between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseAndRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise AND between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseOr(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise OR between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseOrAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise OR between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseOrRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise OR between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseXor(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise XOR between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseXorAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise XOR between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndBitwiseXorRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the result of bitwise XOR between the variable's current value and the `mask` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndSet(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndSetAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getAndSetRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the variable's previous value, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getOpaque(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Returns the value of a variable, accessed in program order, but with no assurance of memory ordering effects with respect to other threads. |
| ` final https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Returns the value of a variable, with memory semantics of reading as if the variable was declared `volatile`. |
| ` final boolean` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#isAccessModeSupported(java.lang.invoke.VarHandle.AccessMode)(https://developer.android.com/reference/java/lang/invoke/VarHandle.AccessMode accessMode) ` Returns `true` if the given access mode is supported, otherwise `false`. |
| ` static void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#loadLoadFence()() ` Ensures that loads before the fence will not be reordered with loads after the fence. |
| ` static void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#releaseFence()() ` Ensures that loads and stores before the fence will not be reordered with stores after the fence. |
| ` final void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Sets the value of a variable to the `newValue`, with memory semantics of setting as if the variable was declared non-`volatile` and non-`final`. |
| ` final void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#setOpaque(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Sets the value of a variable to the `newValue`, in program order, but with no assurance of memory ordering effects with respect to other threads. |
| ` final void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Sets the value of a variable to the `newValue`, and ensures that prior loads and stores are not reordered after this access. |
| ` final void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Sets the value of a variable to the `newValue`, with memory semantics of setting as if the variable was declared `volatile`. |
| ` static void` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#storeStoreFence()() ` Ensures that stores before the fence will not be reordered with stores after the fence. |
| ` final https://developer.android.com/reference/java/lang/invoke/MethodHandle` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#toMethodHandle(java.lang.invoke.VarHandle.AccessMode)(https://developer.android.com/reference/java/lang/invoke/VarHandle.AccessMode accessMode) ` Obtains a method handle bound to this VarHandle and the given access mode. |
| ` final https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#toString()() ` Returns a compact textual description of this [VarHandle](https://developer.android.com/reference/java/lang/invoke/VarHandle), including the type of variable described, and a description of its coordinates. |
| ` final https://developer.android.com/reference/java/lang/Class` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#varType()() ` Returns the variable type of variables referenced by this VarHandle. |
| ` final boolean` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSet(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Possibly atomically sets the value of a variable to the `newValue` with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`. |
| ` final boolean` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSetAcquire(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Possibly atomically sets the value of a variable to the `newValue` with the semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`. |
| ` final boolean` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSetPlain(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Possibly atomically sets the value of a variable to the `newValue` with the semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ` final boolean` | ` https://developer.android.com/reference/java/lang/invoke/VarHandle#weakCompareAndSetRelease(java.lang.Object[])(https://developer.android.com/reference/java/lang/Object args) ` Possibly atomically sets the value of a variable to the `newValue` with the semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` if the variable's current value, referred to as the *witness value* , `==` the `expectedValue`, as accessed with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`. |
| ### Inherited methods |
|---|---|
| From class ` https://developer.android.com/reference/java/lang/Object ` |---|---| | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/Object#clone()() ` Creates and returns a copy of this object. | | ` boolean` | ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` https://developer.android.com/reference/java/lang/Object#finalize()() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final https://developer.android.com/reference/java/lang/Class` | ` https://developer.android.com/reference/java/lang/Object#getClass()() ` Returns the runtime class of this `Object`. | | ` int` | ` https://developer.android.com/reference/java/lang/Object#hashCode()() ` Returns a hash code value for the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notify()() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notifyAll()() ` Wakes up all threads that are waiting on this object's monitor. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/Object#toString()() ` Returns a string representation of the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait()() ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*. | ||
## Public methods
### accessModeType
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final MethodType accessModeType (VarHandle.AccessMode accessMode)
```
Obtains the access mode type for this VarHandle and a given access mode.
The access mode type's parameter types will consist of a prefix that
is the coordinate types of this VarHandle followed by further
types as defined by the access mode method.
The access mode type's return type is defined by the return type of the
access mode method.
| Parameters ||
|---|---|
| `accessMode` | `VarHandle.AccessMode`: the access mode, corresponding to the signature-polymorphic method of the same name
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/invoke/MethodType` | the access mode type for the given access mode
|
### acquireFence
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static void acquireFence ()
```
Ensures that loads before the fence will not be reordered with loads and
stores after the fence.
##### API Note:
- Ignoring the many semantic differences from C and C++, this method has memory ordering effects compatible with `atomic_thread_fence(memory_order_acquire)`
### compareAndExchange
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object compareAndExchange (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` if the variable's current value,
referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)T`.
The symbolic type descriptor at the call site of `compareAndExchange`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.COMPARE_AND_EXCHANGE)`
on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the witness value, which will be the same as the `expectedValue` if successful , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type is compatible with the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type is not compatible with the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### compareAndExchangeAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object compareAndExchangeAcquire (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` if the variable's current value,
referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)T`.
The symbolic type descriptor at the call site of `compareAndExchangeAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.COMPARE_AND_EXCHANGE_ACQUIRE)` on
this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the witness value, which will be the same as the `expectedValue` if successful , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`
### compareAndExchangeRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object compareAndExchangeRelease (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` if the variable's current value,
referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)T`.
The symbolic type descriptor at the call site of `compareAndExchangeRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.COMPARE_AND_EXCHANGE_RELEASE)`
on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the witness value, which will be the same as the `expectedValue` if successful , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`
### compareAndSet
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final boolean compareAndSet (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` if the variable's current value,
referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)boolean`.
The symbolic type descriptor at the call site of `compareAndSet` must match the access mode type that is the result of
calling `accessModeType(VarHandle.AccessMode.COMPARE_AND_SET)` on
this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `boolean` | `true` if successful, otherwise `false` if the witness value was not the same as the `expectedValue`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### coordinateTypes
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final List> coordinateTypes ()
```
Returns the coordinate types for this VarHandle.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/List>` | the coordinate types for this VarHandle. The returned list is unmodifiable
|
### fullFence
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static void fullFence ()
```
Ensures that loads and stores before the fence will not be reordered
with
loads and stores after the fence.
##### API Note:
- Ignoring the many semantic differences from C and C++, this method has memory ordering effects compatible with `atomic_thread_fence(memory_order_seq_cst)`
### get
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object get (Object... args)
```
Returns the value of a variable, with memory semantics of reading as
if the variable was declared non-`volatile`. Commonly referred to
as plain read access.
The method signature is of the form `(CT1 ct1, ..., CTn ctn)T`.
The symbolic type descriptor at the call site of `get`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET)` on this VarHandle.
This access mode is supported by all VarHandle instances and never
throws `UnsupportedOperationException`.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### getAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAcquire (Object... args)
```
Returns the value of a variable, and ensures that subsequent loads and
stores are not reordered before this access.
The method signature is of the form `(CT1 ct1, ..., CTn ctn)T`.
The symbolic type descriptor at the call site of `getAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_ACQUIRE)` on this
VarHandle.
##### API Note:
- Ignoring the many semantic differences from C and C++, this method has memory ordering effects compatible with `memory_order_acquire` ordering.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### getAndAdd
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndAdd (Object... args)
```
Atomically adds the `value` to the current value of a variable with
the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`, and returns the variable's
previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T value)T`.
The symbolic type descriptor at the call site of `getAndAdd`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_ADD)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T value)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndAddAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndAddAcquire (Object... args)
```
Atomically adds the `value` to the current value of a variable with
the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`, and returns the variable's
previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T value)T`.
The symbolic type descriptor at the call site of `getAndAddAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_ADD_ACQUIRE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T value)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndAddRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndAddRelease (Object... args)
```
Atomically adds the `value` to the current value of a variable with
the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`, and returns the variable's
previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T value)T`.
The symbolic type descriptor at the call site of `getAndAddRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_ADD_RELEASE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T value)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndBitwiseAnd
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseAnd (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise AND between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical AND is performed instead of a bitwise AND.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseAnd`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_AND)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndBitwiseAndAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseAndAcquire (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise AND between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical AND is performed instead of a bitwise AND.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseAndAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_AND_ACQUIRE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`
### getAndBitwiseAndRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseAndRelease (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise AND between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical AND is performed instead of a bitwise AND.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseAndRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_AND_RELEASE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`
### getAndBitwiseOr
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseOr (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise OR between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical OR is performed instead of a bitwise OR.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseOr`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_OR)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndBitwiseOrAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseOrAcquire (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise OR between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical OR is performed instead of a bitwise OR.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseOrAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_OR_ACQUIRE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`
### getAndBitwiseOrRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseOrRelease (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise OR between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical OR is performed instead of a bitwise OR.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseOrRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_OR_RELEASE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`
### getAndBitwiseXor
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseXor (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise XOR between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical XOR is performed instead of a bitwise XOR.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseXor`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_XOR)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndBitwiseXorAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseXorAcquire (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise XOR between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical XOR is performed instead of a bitwise XOR.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseXorAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_XOR_ACQUIRE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`
### getAndBitwiseXorRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndBitwiseXorRelease (Object... args)
```
Atomically sets the value of a variable to the result of
bitwise XOR between the variable's current value and the `mask`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the
variable's previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
If the variable type is the non-integral `boolean` type then a
logical XOR is performed instead of a bitwise XOR.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T mask)T`.
The symbolic type descriptor at the call site of `getAndBitwiseXorRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_BITWISE_XOR_RELEASE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T mask)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`
### getAndSet
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndSet (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` and returns the variable's
previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)T`.
The symbolic type descriptor at the call site of `getAndSet`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_SET)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndSetAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndSetAcquire (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` and returns the variable's
previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)T`.
The symbolic type descriptor at the call site of `getAndSetAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_SET_ACQUIRE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getAndSetRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getAndSetRelease (Object... args)
```
Atomically sets the value of a variable to the `newValue` with the
memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` and returns the variable's
previous value, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)T`.
The symbolic type descriptor at the call site of `getAndSetRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_AND_SET_RELEASE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the previous value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### getOpaque
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getOpaque (Object... args)
```
Returns the value of a variable, accessed in program order, but with no
assurance of memory ordering effects with respect to other threads.
The method signature is of the form `(CT1 ct1, ..., CTn ctn)T`.
The symbolic type descriptor at the call site of `getOpaque`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_OPAQUE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### getVolatile
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Object getVolatile (Object... args)
```
Returns the value of a variable, with memory semantics of reading as if
the variable was declared `volatile`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn)T`.
The symbolic type descriptor at the call site of `getVolatile`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.GET_VOLATILE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the signature-polymorphic result that is the value of the variable , statically represented using `Object`.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### isAccessModeSupported
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final boolean isAccessModeSupported (VarHandle.AccessMode accessMode)
```
Returns `true` if the given access mode is supported, otherwise
`false`.
The return of a `false` value for a given access mode indicates
that an `UnsupportedOperationException` is thrown on invocation
of the corresponding access mode method.
| Parameters ||
|---|---|
| `accessMode` | `VarHandle.AccessMode`: the access mode, corresponding to the signature-polymorphic method of the same name
|
| Returns ||
|---|---|
| `boolean` | `true` if the given access mode is supported, otherwise `false`.
|
### loadLoadFence
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static void loadLoadFence ()
```
Ensures that loads before the fence will not be reordered with
loads after the fence.
### releaseFence
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static void releaseFence ()
```
Ensures that loads and stores before the fence will not be
reordered with stores after the fence.
##### API Note:
- Ignoring the many semantic differences from C and C++, this method has memory ordering effects compatible with `atomic_thread_fence(memory_order_release)`
### set
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void set (Object... args)
```
Sets the value of a variable to the `newValue`, with memory
semantics of setting as if the variable was declared non-`volatile`
and non-`final`. Commonly referred to as plain write access.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)void`
The symbolic type descriptor at the call site of `set`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.SET)` on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### setOpaque
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void setOpaque (Object... args)
```
Sets the value of a variable to the `newValue`, in program order,
but with no assurance of memory ordering effects with respect to other
threads.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)void`.
The symbolic type descriptor at the call site of `setOpaque`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.SET_OPAQUE)` on this
VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### setRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void setRelease (Object... args)
```
Sets the value of a variable to the `newValue`, and ensures that
prior loads and stores are not reordered after this access.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)void`.
The symbolic type descriptor at the call site of `setRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.SET_RELEASE)` on this
VarHandle.
##### API Note:
- Ignoring the many semantic differences from C and C++, this method has memory ordering effects compatible with `memory_order_release` ordering.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### setVolatile
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void setVolatile (Object... args)
```
Sets the value of a variable to the `newValue`, with memory
semantics of setting as if the variable was declared `volatile`.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T newValue)void`.
The symbolic type descriptor at the call site of `setVolatile`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.SET_VOLATILE)` on this
VarHandle.
##### API Note:
- Ignoring the many semantic differences from C and C++, this method has memory ordering effects compatible with `memory_order_seq_cst`.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T newValue)` , statically represented using varargs.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
### storeStoreFence
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static void storeStoreFence ()
```
Ensures that stores before the fence will not be reordered with
stores after the fence.
### toMethodHandle
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final MethodHandle toMethodHandle (VarHandle.AccessMode accessMode)
```
Obtains a method handle bound to this VarHandle and the given access
mode.
##### API Note:
- This method, for a VarHandle `vh` and access mode `{access-mode}`, returns a method handle that is equivalent to method handle `bmh` in the following code (though it may be more efficient):
MethodHandle mh = MethodHandles.varHandleExactInvoker(
vh.accessModeType(VarHandle.AccessMode.{access-mode}));
MethodHandle bmh = mh.bindTo(vh);
| Parameters ||
|---|---|
| `accessMode` | `VarHandle.AccessMode`: the access mode, corresponding to the signature-polymorphic method of the same name
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/invoke/MethodHandle` | a method handle bound to this VarHandle and the given access mode
|
### toString
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final String toString ()
```
Returns a compact textual description of this [VarHandle](https://developer.android.com/reference/java/lang/invoke/VarHandle),
including the type of variable described, and a description of its coordinates.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | A compact textual description of this [VarHandle](https://developer.android.com/reference/java/lang/invoke/VarHandle)
|
### varType
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Class varType ()
```
Returns the variable type of variables referenced by this VarHandle.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Class` | the variable type of variables referenced by this VarHandle
|
### weakCompareAndSet
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final boolean weakCompareAndSet (Object... args)
```
Possibly atomically sets the value of a variable to the `newValue`
with the memory semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])` if the variable's
current value, referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`.
This operation may fail spuriously (typically, due to memory
contention) even if the witness value does match the expected value.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)boolean`.
The symbolic type descriptor at the call site of `weakCompareAndSet` must match the access mode type that is the
result of calling `accessModeType(VarHandle.AccessMode.WEAK_COMPARE_AND_SET)`
on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `boolean` | `true` if successful, otherwise `false` if the witness value was not the same as the `expectedValue` or if this operation spuriously failed.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setVolatile(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getVolatile(java.lang.Object[])`
### weakCompareAndSetAcquire
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final boolean weakCompareAndSetAcquire (Object... args)
```
Possibly atomically sets the value of a variable to the `newValue`
with the semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` if the variable's current value,
referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`.
This operation may fail spuriously (typically, due to memory
contention) even if the witness value does match the expected value.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)boolean`.
The symbolic type descriptor at the call site of `weakCompareAndSetAcquire`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.WEAK_COMPARE_AND_SET_ACQUIRE)`
on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `boolean` | `true` if successful, otherwise `false` if the witness value was not the same as the `expectedValue` or if this operation spuriously failed.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#getAcquire(java.lang.Object[])`
### weakCompareAndSetPlain
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final boolean weakCompareAndSetPlain (Object... args)
```
Possibly atomically sets the value of a variable to the `newValue`
with the semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])` if the variable's current value,
referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
This operation may fail spuriously (typically, due to memory
contention) even if the witness value does match the expected value.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)boolean`.
The symbolic type descriptor at the call site of `weakCompareAndSetPlain` must match the access mode type that is the result of
calling `accessModeType(VarHandle.AccessMode.WEAK_COMPARE_AND_SET_PLAIN)`
on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `boolean` | `true` if successful, otherwise `false` if the witness value was not the same as the `expectedValue` or if this operation spuriously failed.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#set(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`
### weakCompareAndSetRelease
Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final boolean weakCompareAndSetRelease (Object... args)
```
Possibly atomically sets the value of a variable to the `newValue`
with the semantics of `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])` if the variable's current
value, referred to as the *witness value* , `==` the
`expectedValue`, as accessed with the memory semantics of
`https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`.
This operation may fail spuriously (typically, due to memory
contention) even if the witness value does match the expected value.
The method signature is of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)boolean`.
The symbolic type descriptor at the call site of `weakCompareAndSetRelease`
must match the access mode type that is the result of calling
`accessModeType(VarHandle.AccessMode.WEAK_COMPARE_AND_SET_RELEASE)`
on this VarHandle.
| Parameters ||
|---|---|
| `args` | `Object`: the signature-polymorphic parameter list of the form `(CT1 ct1, ..., CTn ctn, T expectedValue, T newValue)` , statically represented using varargs.
|
| Returns ||
|---|---|
| `boolean` | `true` if successful, otherwise `false` if the witness value was not the same as the `expectedValue` or if this operation spuriously failed.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the access mode type matches the caller's symbolic type descriptor, but a reference cast fails. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the access mode is unsupported for this VarHandle. |
| `https://developer.android.com/reference/java/lang/invoke/WrongMethodTypeException` | if the access mode type does not match the caller's symbolic type descriptor. |
**See also:**
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#setRelease(java.lang.Object[])`
- `https://developer.android.com/reference/java/lang/invoke/VarHandle#get(java.lang.Object[])`