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The class java.lang.reflect.Array

package java.lang.reflect; public final class Array extends Object The Array class is an uninstantiable class that exports static methods to create Java arrays with primitive or class component types, and to get and set array component values.


Methods

newInstance

public static Object newInstance(Class componentType, int length) throws NullPointerException, NegativeArraySizeException Returns a new array with the specified component type and length. The array is created as if by the equivalent array creation expression, namely:

new componentType[length] The method throws a NullPointerException if the specified componentType argument is null.

The method throws a NegativeArraySizeException if the specified length argument is negative.

newInstance

public static Object newInstance(Class componentType, int[] dimensions) throws NullPointerException, IllegalArgumentException, NegativeArraySizeException Returns a new array with the specified component type and dimensions. The array is created as if by the equivalent array creation expression, namely:

new componentType[dimensions[0]][dimensions[1]]... The method throws a NullPointerException if either the componentType argument or the dimensions argument is null.

The method throws an 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).

The method throws a NegativeArraySizeException if any of the elements of the specified dimensions array is negative.

getLength

public static int getLength(Object array) throws NullPointerException, IllegalArgumentException Returns the length of the specified array.

Throws a NullPointerException if the specified object argument is null.

Throws an IllegalArgumentException if the specified object argument is not an array.

get

public static Object get(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed component of the specified array object. The value is automatically wrapped in an object if it has a primitive type.

The operation proceeds as follows:

Primitive variants of Array.get are also provided for efficiency; these avoid the final wrapping conversion. They are described below.

getBoolean

public static boolean getBoolean(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a boolean. See Array.get for the detailed procedure.

If the indexed value is not of type boolean, the method throws an IllegalArgumentException.

getByte

public static byte getByte(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a byte. See Array.get for the detailed procedure.

If the indexed value is not of type byte, the method throws an IllegalArgumentException.

getChar

public static char getChar(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a char. See Array.get for the detailed procedure.

If the indexed value is not of type char, the method throws an IllegalArgumentException.

getShort

public static short getShort(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a short. See Array.get for the detailed procedure.

If the indexed value cannot be converted to a short by an identity or widening conversion, the method throws an IllegalArgumentException.

getInt

public static int getInt(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as an int. See Array.get for the detailed procedure.

If the indexed value cannot be converted to an int by an identity conversion or a widening conversion, the method throws an IllegalArgumentException.

getLong

public static long getLong(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a long. See Array.get for the detailed procedure.

If the indexed value cannot be converted to a long by an identity conversion or a widening conversion, the method throws an IllegalArgumentException.

getFloat

public static float getFloat(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a float. See Array.get for the detailed procedure.

If the indexed value cannot be converted to a float by an identity conversion or a widening conversion, the method throws an IllegalArgumentException.

getDouble

public static double getDouble(Object array, int index) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Returns the value of the indexed element in the specified array object, as a double. See Array.get for the detailed procedure.

If the indexed value cannot be converted to a double by an identity conversion or a widening conversion, the method throws an IllegalArgumentException.

set

public static void set(Object array, int index, Object value) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets 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.

The operation proceeds as follows:

Primitive variants of Array.set are also provided for efficiency; these let user code avoid having to wrap the new value. They are described below.

setBoolean

public static void setBoolean(Object array, int index, boolean z) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed element of the specified array object to the specified boolean value. See Array.set for the detailed procedure.

setByte

public static void setByte(Object array, int index, byte b) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed element of the specified array object to the specified byte value. See Array.set for the detailed procedure.

setChar

public static void setChar(Object array, int index, char c) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed element of the specified array object to the specified char value. See Array.set for the detailed procedure.

setShort

public static void setShort(Object array, int index, short s) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed component of the specified array object to the specified short value. See Array.set for the detailed procedure.

setInt

public static void setInt(Object array, int index, int i) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed component of the specified array object to the specified int value. See Array.set for the detailed procedure.

setLong

public static void setLong(Object array, int index, long l) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed component of the specified array object to the specified long value. See Array.set for the detailed procedure.

setFloat

public static void setFloat(Object array, int index, float f) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed component of the specified array object to the specified float value. See Array.set for the detailed procedure.

setDouble

public static void setDouble(Object array, int index, double d) throws NullPointerException, IllegalArgumentException, ArrayIndexOutOfBoundsException Sets the indexed component of the specified array object to the specified double value. See Array.set for the detailed procedure.



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