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Array

public final class Array
extends Object

java.lang.Object
   ↳ java.lang.reflect.Array


The Array class provides static methods to dynamically create and access Java arrays.

Array permits widening conversions to occur during a get or set operation, but throws an IllegalArgumentException if a narrowing conversion would occur.

Summary

Public methods

static Object get(Object array, int index)

Returns the value of the indexed component in the specified array object.

static boolean getBoolean(Object array, int index)

Returns the value of the indexed component in the specified array object, as a boolean.

static byte getByte(Object array, int index)

Returns the value of the indexed component in the specified array object, as a byte.

static char getChar(Object array, int index)

Returns the value of the indexed component in the specified array object, as a char.

static double getDouble(Object array, int index)

Returns the value of the indexed component in the specified array object, as a double.

static float getFloat(Object array, int index)

Returns the value of the indexed component in the specified array object, as a float.

static int getInt(Object array, int index)

Returns the value of the indexed component in the specified array object, as an int.

static int getLength(Object array)

Returns the length of the specified array object, as an int.

static long getLong(Object array, int index)

Returns the value of the indexed component in the specified array object, as a long.

static short getShort(Object array, int index)

Returns the value of the indexed component in the specified array object, as a short.

static Object newInstance(Class<?> componentType, int length)

Creates a new array with the specified component type and length.

static Object newInstance(Class<?> componentType, int... dimensions)

Creates a new array with the specified component type and dimensions.

static void set(Object array, int index, Object value)

Sets the value of the indexed component of the specified array object to the specified new value.

static void setBoolean(Object array, int index, boolean value)

Sets the value of the indexed component of the specified array object to the specified boolean value.

static void setByte(Object array, int index, byte value)

Sets the value of the indexed component of the specified array object to the specified byte value.

static void setChar(Object array, int index, char value)

Sets the value of the indexed component of the specified array object to the specified char value.

static void setDouble(Object array, int index, double value)

Sets the value of the indexed component of the specified array object to the specified double value.

static void setFloat(Object array, int index, float value)

Sets the value of the indexed component of the specified array object to the specified float value.

static void setInt(Object array, int index, int value)

Sets the value of the indexed component of the specified array object to the specified int value.

static void setLong(Object array, int index, long value)

Sets the value of the indexed component of the specified array object to the specified long value.

static void setShort(Object array, int index, short value)

Sets the value of the indexed component of the specified array object to the specified short value.

Inherited methods

From class java.lang.Object

Public methods

get

Added in API level 1
Object get (Object array, 
                int index)

Returns the value of the indexed component in the specified array object. The value is automatically wrapped in an object if it has a primitive type.

Parameters
array Object: the array
index int: the index
Returns
Object the (possibly wrapped) value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

getBoolean

Added in API level 1
boolean getBoolean (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a boolean.

Parameters
array Object: the array
index int: the index
Returns
boolean the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getByte

Added in API level 1
byte getByte (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a byte.

Parameters
array Object: the array
index int: the index
Returns
byte the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getChar

Added in API level 1
char getChar (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a char.

Parameters
array Object: the array
index int: the index
Returns
char the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getDouble

Added in API level 1
double getDouble (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a double.

Parameters
array Object: the array
index int: the index
Returns
double the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getFloat

Added in API level 1
float getFloat (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a float.

Parameters
array Object: the array
index int: the index
Returns
float the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getInt

Added in API level 1
int getInt (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as an int.

Parameters
array Object: the array
index int: the index
Returns
int the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getLength

Added in API level 1
int getLength (Object array)

Returns the length of the specified array object, as an int.

Parameters
array Object: the array
Returns
int the length of the array
Throws
IllegalArgumentException if the object argument is not an array

getLong

Added in API level 1
long getLong (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a long.

Parameters
array Object: the array
index int: the index
Returns
long the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

getShort

Added in API level 1
short getShort (Object array, 
                int index)

Returns the value of the indexed component in the specified array object, as a short.

Parameters
array Object: the array
index int: the index
Returns
short the value of the indexed component in the specified array
Throws
NullPointerException If the specified object is null
IllegalArgumentException If the specified object is not an array, or if the indexed element cannot be converted to the return type by an identity or widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

newInstance

Added in API level 1
Object newInstance (Class<?> componentType, 
                int length)

Creates a new array with the specified component type and length. Invoking this method is equivalent to creating an array as follows:

 int[] x = {length};
 Array.newInstance(componentType, x);
 

Parameters
componentType Class: the Class object representing the component type of the new array
length int: the length of the new array
Returns
Object the new array
Throws
NullPointerException if the specified componentType parameter is null
IllegalArgumentException if componentType is TYPE
NegativeArraySizeException if the specified length is negative

newInstance

Added in API level 9
Object newInstance (Class<?> componentType, 
                int... dimensions)

Creates a new array with the specified component type and dimensions. If componentType represents a non-array class or interface, the new array has dimensions.length dimensions and componentType as its component type. If componentType represents an array class, the number of dimensions of the new array is equal to the sum of dimensions.length and the number of dimensions of componentType. In this case, the component type of the new array is the component type of componentType.

The number of dimensions of the new array must not exceed the number of array dimensions supported by the implementation (typically 255).

Parameters
componentType Class: the Class object representing the component type of the new array
dimensions int: an array of int representing the dimensions of the new array
Returns
Object the new array
Throws
NullPointerException if the specified componentType argument is null
IllegalArgumentException if the specified dimensions argument is a zero-dimensional array, or if the number of requested dimensions exceeds the limit on the number of array dimensions supported by the implementation (typically 255), or if componentType is TYPE.
NegativeArraySizeException if any of the components in the specified dimensions argument is negative.

set

Added in API level 1
void set (Object array, 
                int index, 
                Object value)

Sets the value of the indexed component of the specified array object to the specified new value. The new value is first automatically unwrapped if the array has a primitive component type.

Parameters
array Object: the array
index int: the index into the array
value Object: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the array component type is primitive and an unwrapping conversion fails
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

setBoolean

Added in API level 1
void setBoolean (Object array, 
                int index, 
                boolean value)

Sets the value of the indexed component of the specified array object to the specified boolean value.

Parameters
array Object: the array
index int: the index into the array
value boolean: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setByte

Added in API level 1
void setByte (Object array, 
                int index, 
                byte value)

Sets the value of the indexed component of the specified array object to the specified byte value.

Parameters
array Object: the array
index int: the index into the array
value byte: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setChar

Added in API level 1
void setChar (Object array, 
                int index, 
                char value)

Sets the value of the indexed component of the specified array object to the specified char value.

Parameters
array Object: the array
index int: the index into the array
value char: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setDouble

Added in API level 1
void setDouble (Object array, 
                int index, 
                double value)

Sets the value of the indexed component of the specified array object to the specified double value.

Parameters
array Object: the array
index int: the index into the array
value double: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setFloat

Added in API level 1
void setFloat (Object array, 
                int index, 
                float value)

Sets the value of the indexed component of the specified array object to the specified float value.

Parameters
array Object: the array
index int: the index into the array
value float: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setInt

Added in API level 1
void setInt (Object array, 
                int index, 
                int value)

Sets the value of the indexed component of the specified array object to the specified int value.

Parameters
array Object: the array
index int: the index into the array
value int: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setLong

Added in API level 1
void setLong (Object array, 
                int index, 
                long value)

Sets the value of the indexed component of the specified array object to the specified long value.

Parameters
array Object: the array
index int: the index into the array
value long: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

setShort

Added in API level 1
void setShort (Object array, 
                int index, 
                short value)

Sets the value of the indexed component of the specified array object to the specified short value.

Parameters
array Object: the array
index int: the index into the array
value short: the new value of the indexed component
Throws
NullPointerException If the specified object argument is null
IllegalArgumentException If the specified object argument is not an array, or if the specified value cannot be converted to the underlying array's component type by an identity or a primitive widening conversion
ArrayIndexOutOfBoundsException If the specified index argument is negative, or if it is greater than or equal to the length of the specified array

See also:

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