Array

public final class Array extends Object

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.

Public Method Summary

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 Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Public Methods

public static 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	the array
index	the index

Returns

• 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

public static boolean getBoolean (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static byte getByte (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static char getChar (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static double getDouble (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static float getFloat (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static int getInt (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static int getLength (Object array)

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

Parameters

array	the array

Returns

• the length of the array

Throws

IllegalArgumentException	if the object argument is not an array

public static long getLong (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static short getShort (Object array, int index)

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

Parameters

array	the array
index	the index

Returns

• 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

• get(Object, int)

public static 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);
 

The number of dimensions of the new array must not exceed 255.

Parameters

componentType	the Class object representing the component type of the new array
length	the length of the new array

Returns

• the new array

Throws

NullPointerException	if the specified componentType parameter is null
IllegalArgumentException	if componentType is Void.TYPE or if the number of dimensions of the requested array instance exceed 255.
NegativeArraySizeException	if the specified length is negative

public static 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 255.

Parameters

componentType	the Class object representing the component type of the new array
dimensions	an array of int representing the dimensions of the new array

Returns

• the new array

Throws

NullPointerException	if the specified componentType argument is null
IllegalArgumentException	if the specified dimensions argument is a zero-dimensional array, if componentType is Void.TYPE, or if the number of dimensions of the requested array instance exceed 255.
NegativeArraySizeException	if any of the components in the specified dimensions argument is negative.

public 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. The new value is first automatically unwrapped if the array has a primitive component type.

Parameters

array	the array
index	the index into the array
value	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

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)

public 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.

Parameters

array	the array
index	the index into the array
value	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

• set(Object, int, Object)