java.util.Arrays

Arrays

Java SE 6

This class contains various methods for manipulating arrays (such as sorting and searching). This class also contains a static factory that allows arrays to be viewed as lists.

The methods in this class all throw a NullPointerException if the specified array reference is null, except where noted.

The documentation for the methods contained in this class includes briefs description of the implementations. Such descriptions should be regarded as implementation notes, rather than parts of the specification. Implementors should feel free to substitute other algorithms, so long as the specification itself is adhered to. (For example, the algorithm used by sort(Object[]) does not have to be a mergesort, but it does have to be stable.)

This class is a member of the Java Collections Framework.

version 1.71, 04/21/06

since 1.2

Methods

public static List<T>

asList(Object[] a)
Returns a fixed-size list backed by the specified array. (Changes to the returned list "write through" to the array.) This method acts as bridge between array-based and collection-based APIs, in combination with Collection#toArray. The returned list is serializable and implements RandomAccess.

This method also provides a convenient way to create a fixed-size list initialized to contain several elements:

     List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");

a	the array by which the list will be backed
return	a list view of the specified array

public static int

binarySearch(long[] a, long key)
Searches the specified array of longs for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(long[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(long[] a, int fromIndex, int toIndex, long key)
Searches a range of the specified array of longs for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(int[] a, int key)
Searches the specified array of ints for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(int[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(int[] a, int fromIndex, int toIndex, int key)
Searches a range of the specified array of ints for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(short[] a, short key)
Searches the specified array of shorts for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(short[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(short[] a, int fromIndex, int toIndex, short key)
Searches a range of the specified array of shorts for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(char[] a, char key)
Searches the specified array of chars for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(char[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(char[] a, int fromIndex, int toIndex, char key)
Searches a range of the specified array of chars for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(byte[] a, byte key)
Searches the specified array of bytes for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(byte[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(byte[] a, int fromIndex, int toIndex, byte key)
Searches a range of the specified array of bytes for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(double[] a, double key)
Searches the specified array of doubles for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(double[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found. This method considers all NaN values to be equivalent and equal.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(double[] a, int fromIndex, int toIndex, double key)
Searches a range of the specified array of doubles for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found. This method considers all NaN values to be equivalent and equal.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(float[] a, float key)
Searches the specified array of floats for the specified value using the binary search algorithm. The array must be sorted (as by the #sort(float[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found. This method considers all NaN values to be equivalent and equal.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

public static int

binarySearch(float[] a, int fromIndex, int toIndex, float key)
Searches a range of the specified array of floats for the specified value using the binary search algorithm. The range must be sorted (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found. This method considers all NaN values to be equivalent and equal.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int

binarySearch(Object[] a, Object key)
Searches the specified array for the specified object using the binary search algorithm. The array must be sorted into ascending order according to the natural ordering of its elements (as by the #sort(Object[]) method) prior to making this call. If it is not sorted, the results are undefined. (If the array contains elements that are not mutually comparable (for example, strings and integers), it cannot be sorted according to the natural ordering of its elements, hence results are undefined.) If the array contains multiple elements equal to the specified object, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	ClassCastException: if the search key is not comparable to the elements of the array.

public static int

binarySearch(Object[] a, int fromIndex, int toIndex, Object key)
Searches a range of the specified array for the specified object using the binary search algorithm. The range must be sorted into ascending order according to the natural ordering of its elements (as by the int, int) method) prior to making this call. If it is not sorted, the results are undefined. (If the range contains elements that are not mutually comparable (for example, strings and integers), it cannot be sorted according to the natural ordering of its elements, hence results are undefined.) If the range contains multiple elements equal to the specified object, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	ClassCastException: if the search key is not comparable to the elements of the array within the specified range.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static int<T>

binarySearch(Object[] a, Object key, Comparator c)
Searches the specified array for the specified object using the binary search algorithm. The array must be sorted into ascending order according to the specified comparator (as by the sort(T[], Comparator) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements equal to the specified object, there is no guarantee which one will be found.

a	the array to be searched
key	the value to be searched for
c	the comparator by which the array is ordered. A `null` value indicates that the elements' natural ordering should be used.
return	index of the search key, if it is contained in the array; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or `a.length` if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	ClassCastException: if the array contains elements that are not mutually comparable using the specified comparator, or the search key is not comparable to the elements of the array using this comparator.

public static int<T>

binarySearch(Object[] a, int fromIndex, int toIndex, Object key, Comparator c)
Searches a range of the specified array for the specified object using the binary search algorithm. The range must be sorted into ascending order according to the specified comparator (as by the sort(T[], int, int, Comparator) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements equal to the specified object, there is no guarantee which one will be found.

a	the array to be searched
fromIndex	the index of the first element (inclusive) to be searched
toIndex	the index of the last element (exclusive) to be searched
key	the value to be searched for
c	the comparator by which the array is ordered. A `null` value indicates that the elements' natural ordering should be used.
return	index of the search key, if it is contained in the array within the specified range; otherwise, `(-(insertion point) - 1)`. The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or `toIndex` if all elements in the range are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws	ClassCastException: if the range contains elements that are not mutually comparable using the specified comparator, or the search key is not comparable to the elements in the range using this comparator.
Throws	IllegalArgumentException: if `fromIndex > toIndex`if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0 or toIndex > a.length`
since	1.6

public static Object[]<T>

copyOf(Object[] original, int newLength)
Copies the specified array, truncating or padding with nulls (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain null. Such indices will exist if and only if the specified length is greater than that of the original array. The resulting array is of exactly the same class as the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with nulls to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static Object[]<T, U>

copyOf(Object[] original, int newLength, Class newType)
Copies the specified array, truncating or padding with nulls (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain null. Such indices will exist if and only if the specified length is greater than that of the original array. The resulting array is of the class newType.

original	the array to be copied
newLength	the length of the copy to be returned
newType	the class of the copy to be returned
return	a copy of the original array, truncated or padded with nulls to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
Throws	ArrayStoreException: if an element copied from `original` is not of a runtime type that can be stored in an array of class `newType`
since	1.6

public static byte[]

copyOf(byte[] original, int newLength)
Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain (byte)0. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static short[]

copyOf(short[] original, int newLength)
Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain (short)0. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static int[]

copyOf(int[] original, int newLength)
Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain 0. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static long[]

copyOf(long[] original, int newLength)
Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain 0L. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static char[]

copyOf(char[] original, int newLength)
Copies the specified array, truncating or padding with null characters (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain '\\u000'. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with null characters to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static float[]

copyOf(float[] original, int newLength)
Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain 0f. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static double[]

copyOf(double[] original, int newLength)
Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain 0d. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static boolean[]

copyOf(boolean[] original, int newLength)
Copies the specified array, truncating or padding with false (if necessary) so the copy has the specified length. For all indices that are valid in both the original array and the copy, the two arrays will contain identical values. For any indices that are valid in the copy but not the original, the copy will contain false. Such indices will exist if and only if the specified length is greater than that of the original array.

original	the array to be copied
newLength	the length of the copy to be returned
return	a copy of the original array, truncated or padded with false elements to obtain the specified length
Throws	NegativeArraySizeException: if `newLength` is negative
Throws	NullPointerException: if `original` is null
since	1.6

public static Object[]<T>

copyOfRange(Object[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case null is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

The resulting array is of exactly the same class as the original array.

original the array from which a range is to be copied

from the initial index of the range to be copied, inclusive

to the final index of the range to be copied, exclusive. (This index may lie outside the array.)

return a new array containing the specified range from the original array, truncated or padded with nulls to obtain the required length

Throws ArrayIndexOutOfBoundsException: if from < 0 or from > original.length()

Throws IllegalArgumentException: if from > to

Throws NullPointerException: if original is null

since 1.6

public static Object[]<T, U>

copyOfRange(Object[] original, int from, int to, Class newType)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case null is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from. The resulting array is of the class newType.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
newType	the class of the copy to be returned
return	a new array containing the specified range from the original array, truncated or padded with nulls to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
Throws	ArrayStoreException: if an element copied from `original` is not of a runtime type that can be stored in an array of class `newType`.
since	1.6

public static byte[]

copyOfRange(byte[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case (byte)0 is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static short[]

copyOfRange(short[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case (short)0 is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static int[]

copyOfRange(int[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case 0 is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static long[]

copyOfRange(long[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case 0L is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static char[]

copyOfRange(char[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case '\\u000' is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with null characters to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static float[]

copyOfRange(float[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case 0f is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static double[]

copyOfRange(double[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case 0d is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static boolean[]

copyOfRange(boolean[] original, int from, int to)
Copies the specified range of the specified array into a new array. The initial index of the range (from) must lie between zero and original.length, inclusive. The value at original[from] is placed into the initial element of the copy (unless from == original.length or from == to). Values from subsequent elements in the original array are placed into subsequent elements in the copy. The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case false is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

original	the array from which a range is to be copied
from	the initial index of the range to be copied, inclusive
to	the final index of the range to be copied, exclusive. (This index may lie outside the array.)
return	a new array containing the specified range from the original array, truncated or padded with false elements to obtain the required length
Throws	ArrayIndexOutOfBoundsException: if `from < 0` or `from > original.length()`
Throws	IllegalArgumentException: if `from > to`
Throws	NullPointerException: if `original` is null
since	1.6

public static boolean

deepEquals(Object[] a1, Object[] a2)
Returns true if the two specified arrays are deeply equal to one another. Unlike the #equals(Object[],Object[]) method, this method is appropriate for use with nested arrays of arbitrary depth.

Two array references are considered deeply equal if both are null, or if they refer to arrays that contain the same number of elements and all corresponding pairs of elements in the two arrays are deeply equal.

Two possibly null elements e1 and e2 are deeply equal if any of the following conditions hold:

e1 and e2 are both arrays of object reference types, and Arrays.deepEquals(e1, e2) would return true
e1 and e2 are arrays of the same primitive type, and the appropriate overloading of Arrays.equals(e1, e2) would return true.
e1 == e2
e1.equals(e2) would return true.

Note that this definition permits null elements at any depth.

If either of the specified arrays contain themselves as elements either directly or indirectly through one or more levels of arrays, the behavior of this method is undefined.

a1 one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

since 1.5

See also equals(Object[],Object[])

public static int

deepHashCode(Object[] a)
Returns a hash code based on the "deep contents" of the specified array. If the array contains other arrays as elements, the hash code is based on their contents and so on, ad infinitum. It is therefore unacceptable to invoke this method on an array that contains itself as an element, either directly or indirectly through one or more levels of arrays. The behavior of such an invocation is undefined.

For any two arrays a and b such that Arrays.deepEquals(a, b), it is also the case that Arrays.deepHashCode(a) == Arrays.deepHashCode(b).

The computation of the value returned by this method is similar to that of the value returned by List#hashCode() on a list containing the same elements as a in the same order, with one difference: If an element e of a is itself an array, its hash code is computed not by calling e.hashCode(), but as by calling the appropriate overloading of Arrays.hashCode(e) if e is an array of a primitive type, or as by calling Arrays.deepHashCode(e) recursively if e is an array of a reference type. If a is null, this method returns 0.

a the array whose deep-content-based hash code to compute

return a deep-content-based hash code for a

since 1.5

See also hashCode(Object[])

public static String

deepToString(Object[] a)
Returns a string representation of the "deep contents" of the specified array. If the array contains other arrays as elements, the string representation contains their contents and so on. This method is designed for converting multidimensional arrays to strings.

The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(Object), unless they are themselves arrays.

If an element e is an array of a primitive type, it is converted to a string as by invoking the appropriate overloading of Arrays.toString(e). If an element e is an array of a reference type, it is converted to a string as by invoking this method recursively.

To avoid infinite recursion, if the specified array contains itself as an element, or contains an indirect reference to itself through one or more levels of arrays, the self-reference is converted to the string "[...]". For example, an array containing only a reference to itself would be rendered as "[[...]]".

This method returns "null" if the specified array is null.

a the array whose string representation to return

return a string representation of a

since 1.5

See also toString(Object[])

public static boolean

equals(long[] a, long[] a2)
Returns true if the two specified arrays of longs are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static boolean

equals(int[] a, int[] a2)
Returns true if the two specified arrays of ints are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static boolean

equals(short[] a, short[] a2)
Returns true if the two specified arrays of shorts are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static boolean

equals(char[] a, char[] a2)
Returns true if the two specified arrays of chars are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static boolean

equals(byte[] a, byte[] a2)
Returns true if the two specified arrays of bytes are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static boolean

equals(boolean[] a, boolean[] a2)
Returns true if the two specified arrays of booleans are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static boolean

equals(double[] a, double[] a2)
Returns true if the two specified arrays of doubles are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

Two doubles d1 and d2 are considered equal if:

    new Double(d1).equals(new Double(d2))

(Unlike the == operator, this method considers NaN equals to itself, and 0.0d unequal to -0.0d.)

a	one array to be tested for equality
a2	the other array to be tested for equality
return	`true` if the two arrays are equal
See also	equals(Object)

public static boolean

equals(float[] a, float[] a2)
Returns true if the two specified arrays of floats are equal to one another. Two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. In other words, two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

Two floats f1 and f2 are considered equal if:

    new Float(f1).equals(new Float(f2))

(Unlike the == operator, this method considers NaN equals to itself, and 0.0f unequal to -0.0f.)

a	one array to be tested for equality
a2	the other array to be tested for equality
return	`true` if the two arrays are equal
See also	equals(Object)

public static boolean

equals(Object[] a, Object[] a2)
Returns true if the two specified arrays of Objects are equal to one another. The two arrays are considered equal if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equal. Two objects e1 and e2 are considered equal if (e1==null ? e2==null : e1.equals(e2)). In other words, the two arrays are equal if they contain the same elements in the same order. Also, two array references are considered equal if both are null.

a one array to be tested for equality

a2 the other array to be tested for equality

return true if the two arrays are equal

public static void

fill(long[] a, long val)
Assigns the specified long value to each element of the specified array of longs.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(long[] a, int fromIndex, int toIndex, long val)
Assigns the specified long value to each element of the specified range of the specified array of longs. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(int[] a, int val)
Assigns the specified int value to each element of the specified array of ints.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(int[] a, int fromIndex, int toIndex, int val)
Assigns the specified int value to each element of the specified range of the specified array of ints. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(short[] a, short val)
Assigns the specified short value to each element of the specified array of shorts.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(short[] a, int fromIndex, int toIndex, short val)
Assigns the specified short value to each element of the specified range of the specified array of shorts. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(char[] a, char val)
Assigns the specified char value to each element of the specified array of chars.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(char[] a, int fromIndex, int toIndex, char val)
Assigns the specified char value to each element of the specified range of the specified array of chars. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(byte[] a, byte val)
Assigns the specified byte value to each element of the specified array of bytes.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(byte[] a, int fromIndex, int toIndex, byte val)
Assigns the specified byte value to each element of the specified range of the specified array of bytes. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(boolean[] a, boolean val)
Assigns the specified boolean value to each element of the specified array of booleans.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(boolean[] a, int fromIndex, int toIndex, boolean val)
Assigns the specified boolean value to each element of the specified range of the specified array of booleans. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(double[] a, double val)
Assigns the specified double value to each element of the specified array of doubles.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(double[] a, int fromIndex, int toIndex, double val)
Assigns the specified double value to each element of the specified range of the specified array of doubles. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(float[] a, float val)
Assigns the specified float value to each element of the specified array of floats.

a	the array to be filled
val	the value to be stored in all elements of the array

public static void

fill(float[] a, int fromIndex, int toIndex, float val)
Assigns the specified float value to each element of the specified range of the specified array of floats. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`

public static void

fill(Object[] a, Object val)
Assigns the specified Object reference to each element of the specified array of Objects.

a	the array to be filled
val	the value to be stored in all elements of the array
Throws	ArrayStoreException: if the specified value is not of a runtime type that can be stored in the specified array

public static void

fill(Object[] a, int fromIndex, int toIndex, Object val)
Assigns the specified Object reference to each element of the specified range of the specified array of Objects. The range to be filled extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be filled is empty.)

a	the array to be filled
fromIndex	the index of the first element (inclusive) to be filled with the specified value
toIndex	the index of the last element (exclusive) to be filled with the specified value
val	the value to be stored in all elements of the array
Throws	IllegalArgumentException: if `fromIndex > toIndex`
Throws	ArrayIndexOutOfBoundsException: if `fromIndex < 0` or `toIndex > a.length`
Throws	ArrayStoreException: if the specified value is not of a runtime type that can be stored in the specified array

public static int

hashCode(long[] a)
Returns a hash code based on the contents of the specified array. For any two long arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Long instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(int[] a)
Returns a hash code based on the contents of the specified array. For any two non-null int arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Integer instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(short[] a)
Returns a hash code based on the contents of the specified array. For any two short arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Short instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(char[] a)
Returns a hash code based on the contents of the specified array. For any two char arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Character instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(byte[] a)
Returns a hash code based on the contents of the specified array. For any two byte arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Byte instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(boolean[] a)
Returns a hash code based on the contents of the specified array. For any two boolean arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Boolean instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(float[] a)
Returns a hash code based on the contents of the specified array. For any two float arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Float instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(double[] a)
Returns a hash code based on the contents of the specified array. For any two double arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Double instances representing the elements of a in the same order. If a is null, this method returns 0.

a the array whose hash value to compute

return a content-based hash code for a

since 1.5

public static int

hashCode(Object[] a)
Returns a hash code based on the contents of the specified array. If the array contains other arrays as elements, the hash code is based on their identities rather than their contents. It is therefore acceptable to invoke this method on an array that contains itself as an element, either directly or indirectly through one or more levels of arrays.

For any two arrays a and b such that Arrays.equals(a, b), it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b).

The value returned by this method is equal to the value that would be returned by Arrays.asList(a).hashCode(), unless a is null, in which case 0 is returned.

a the array whose content-based hash code to compute

return a content-based hash code for a

since 1.5

See also deepHashCode(Object[])

public static void

sort(long[] a)
Sorts the specified array of longs into ascending numerical order. The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.

a	the array to be sorted

public static void

sort(long[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of longs into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.

a the array to be sorted

fromIndex the index of the first element (inclusive) to be sorted

toIndex the index of the last element (exclusive) to be sorted

Throws IllegalArgumentException: if fromIndex > toIndex

Throws ArrayIndexOutOfBoundsException: if fromIndex < 0 or toIndex > a.length

public static void

sort(int[] a)
Sorts the specified array of ints into ascending numerical order. The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.

a	the array to be sorted

public static void

sort(int[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of ints into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

public static void

sort(short[] a)
Sorts the specified array of shorts into ascending numerical order. The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.

a	the array to be sorted

public static void

sort(short[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of shorts into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

public static void

sort(char[] a)
Sorts the specified array of chars into ascending numerical order. The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.

a	the array to be sorted

public static void

sort(char[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of chars into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

public static void

sort(byte[] a)
Sorts the specified array of bytes into ascending numerical order. The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.

a	the array to be sorted

public static void

sort(byte[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of bytes into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

public static void

sort(double[] a)
Sorts the specified array of doubles into ascending numerical order.

The < relation does not provide a total order on all floating-point values; although they are distinct numbers -0.0 == 0.0 is true and a NaN value compares neither less than, greater than, nor equal to any floating-point value, even itself. To allow the sort to proceed, instead of using the < relation to determine ascending numerical order, this method uses the total order imposed by Double#compareTo. This ordering differs from the < relation in that -0.0 is treated as less than 0.0 and NaN is considered greater than any other floating-point value. For the purposes of sorting, all NaN values are considered equivalent and equal.

public static void

sort(double[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of doubles into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

public static void

sort(float[] a)
Sorts the specified array of floats into ascending numerical order.

The < relation does not provide a total order on all floating-point values; although they are distinct numbers -0.0f == 0.0f is true and a NaN value compares neither less than, greater than, nor equal to any floating-point value, even itself. To allow the sort to proceed, instead of using the < relation to determine ascending numerical order, this method uses the total order imposed by Float#compareTo. This ordering differs from the < relation in that -0.0f is treated as less than 0.0f and NaN is considered greater than any other floating-point value. For the purposes of sorting, all NaN values are considered equivalent and equal.

public static void

sort(float[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of floats into ascending numerical order. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.)

public static void

sort(Object[] a)
Sorts the specified array of objects into ascending order, according to the natural ordering of its elements. All elements in the array must implement the Comparable interface. Furthermore, all elements in the array must be mutually comparable (that is, e1.compareTo(e2) must not throw a ClassCastException for any elements e1 and e2 in the array).

This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort.

The sorting algorithm is a modified mergesort (in which the merge is omitted if the highest element in the low sublist is less than the lowest element in the high sublist). This algorithm offers guaranteed n*log(n) performance.

a the array to be sorted

Throws ClassCastException: if the array contains elements that are not mutually comparable (for example, strings and integers).

public static void

sort(Object[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of objects into ascending order, according to the natural ordering of its elements. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.) All elements in this range must implement the Comparable interface. Furthermore, all elements in this range must be mutually comparable (that is, e1.compareTo(e2) must not throw a ClassCastException for any elements e1 and e2 in the array).

This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort.

The sorting algorithm is a modified mergesort (in which the merge is omitted if the highest element in the low sublist is less than the lowest element in the high sublist). This algorithm offers guaranteed n*log(n) performance.

a the array to be sorted

fromIndex the index of the first element (inclusive) to be sorted

toIndex the index of the last element (exclusive) to be sorted

Throws IllegalArgumentException: if fromIndex > toIndex

Throws ArrayIndexOutOfBoundsException: if fromIndex < 0 or toIndex > a.length

Throws ClassCastException: if the array contains elements that are not mutually comparable (for example, strings and integers).

public static void<T>

sort(Object[] a, Comparator c)
Sorts the specified array of objects according to the order induced by the specified comparator. All elements in the array must be mutually comparable by the specified comparator (that is, c.compare(e1, e2) must not throw a ClassCastException for any elements e1 and e2 in the array).

This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort.

public static void<T>

sort(Object[] a, int fromIndex, int toIndex, Comparator c)
Sorts the specified range of the specified array of objects according to the order induced by the specified comparator. The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive. (If fromIndex==toIndex, the range to be sorted is empty.) All elements in the range must be mutually comparable by the specified comparator (that is, c.compare(e1, e2) must not throw a ClassCastException for any elements e1 and e2 in the range).

This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort.

The sorting algorithm is a modified mergesort (in which the merge is omitted if the highest element in the low sublist is less than the lowest element in the high sublist). This algorithm offers guaranteed n*log(n) performance.

a the array to be sorted

fromIndex the index of the first element (inclusive) to be sorted

toIndex the index of the last element (exclusive) to be sorted

c the comparator to determine the order of the array. A null value indicates that the elements' natural ordering should be used.

Throws ClassCastException: if the array contains elements that are not mutually comparable using the specified comparator.

Throws IllegalArgumentException: if fromIndex > toIndex

Throws ArrayIndexOutOfBoundsException: if fromIndex < 0 or toIndex > a.length

public static String

toString(long[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(long). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(int[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(int). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(short[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(short). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(char[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(char). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(byte[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(byte). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(boolean[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(boolean). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(float[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(float). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(double[] a)
Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(double). Returns "null" if a is null.

a	the array whose string representation to return
return	a string representation of `a`
since	1.5

public static String

toString(Object[] a)
Returns a string representation of the contents of the specified array. If the array contains other arrays as elements, they are converted to strings by the Object#toString method inherited from Object, which describes their identities rather than their contents.

The value returned by this method is equal to the value that would be returned by Arrays.asList(a).toString(), unless a is null, in which case "null" is returned.

a the array whose string representation to return

return a string representation of a

since 1.5

See also deepToString(Object[])

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Java SE 6