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NullPointerException
public
class
NullPointerException
extends RuntimeException
Thrown when an application attempts to use null
in a
case where an object is required. These include:
- Calling the instance method of a
null
object.
- Accessing or modifying the field of a
null
object.
- Taking the length of
null
as if it were an array.
- Accessing or modifying the slots of
null
as if it
were an array.
- Throwing
null
as if it were a Throwable
value.
Applications should throw instances of this class to indicate
other illegal uses of the null
object.
NullPointerException
objects may be constructed by the
virtual machine as if stack trace was not writable.
Summary
Inherited methods |
|
From class
java.lang.Object
Object
|
clone()
Creates and returns a copy of this object.
|
boolean
|
equals(Object obj)
Indicates whether some other object is "equal to" this one.
|
void
|
finalize()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
|
final
Class<?>
|
getClass()
Returns the runtime class of this Object .
|
int
|
hashCode()
Returns a hash code value for the object.
|
final
void
|
notify()
Wakes up a single thread that is waiting on this object's
monitor.
|
final
void
|
notifyAll()
Wakes up all threads that are waiting on this object's monitor.
|
String
|
toString()
Returns a string representation of the object.
|
final
void
|
wait(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
|
wait(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
|
wait()
Causes the current thread to wait until it is awakened, typically
by being notified or interrupted.
|
|
Public constructors
NullPointerException
public NullPointerException ()
Constructs a NullPointerException
with no detail message.
NullPointerException
public NullPointerException (String s)
Constructs a NullPointerException
with the specified
detail message.
Parameters |
s |
String : the detail message. |
Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
Last updated 2023-02-08 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2023-02-08 UTC."],[],[]]