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java.util
Class Arrays
java.lang.Object
java.util.Arrays

public class
Arrays

extends
Object
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.
null.
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
.

Since:

1.2

See Also:

Comparable
,
Comparator
Method Summary

static

asList
(T[] a)
Returns a fixedsize list backed by the specified array.

static int 
binarySearch
(byte[] a, byte key)
Searches the specified array of bytes for the specified value using the binary search algorithm. 
static int 
binarySearch
(char[] a, char key)
Searches the specified array of chars for the specified value using the binary search algorithm. 
static int 
binarySearch
(double[] a, double key)
Searches the specified array of doubles for the specified value using the binary search algorithm. 
static int 
binarySearch
(float[] a, float key)
Searches the specified array of floats for the specified value using the binary search algorithm. 
static int 
binarySearch
(int[] a, int key)
Searches the specified array of ints for the specified value using the binary search algorithm. 
static int 
binarySearch
(long[] a, long key)
Searches the specified array of longs for the specified value using the binary search algorithm. 
static int 
binarySearch
(
Object
[] a,
Object
key)
Searches the specified array for the specified object using the binary search algorithm. 
static int

binarySearch
(
Object
[] a,
Object
key,
Comparator
Searches the specified array for the specified object using the binary search algorithm.

static int 
binarySearch
(short[] a, short key)
Searches the specified array of shorts for the specified value using the binary search algorithm. 
static
<T> int


binarySearch
(T[] a, T key,
Comparator
<? super T> c)
Searches the specified array for the specified object using the binary search algorithm.

static boolean

deepEquals
(
Object
[] a1,
Object
Returns
true
if the two specified arrays are
deeply equal
to one another.

static int

deepHashCode
(
Object
Returns a hash code based on the "deep contents" of the specified array.

static
String

deepToString
(
Object
Returns a string representation of the "deep contents" of the specified array.

static boolean 
equals
(boolean[] a, boolean[] a2)
Returns
true
if the two specified arrays of booleans are
equal
to one another. 
static boolean 
equals
(byte[] a, byte[] a2)
Returns
true
if the two specified arrays of bytes are
equal
to one another. 
static boolean 
equals
(char[] a, char[] a2)
Returns
true
if the two specified arrays of chars are
equal
to one another. 
static boolean 
equals
(double[] a, double[] a2)
Returns
true
if the two specified arrays of doubles are
equal
to one another. 
static boolean 
equals
(float[] a, float[] a2)
Returns
true
if the two specified arrays of floats are
equal
to one another. 
static boolean 
equals
(int[] a, int[] a2)
Returns
true
if the two specified arrays of ints are
equal
to one another. 
static boolean 
equals
(long[] a, long[] a2)
Returns
true
if the two specified arrays of longs are
equal
to one another. 
static boolean 
equals
(
Object
[] a,
Object
[] a2)
Returns
true
if the two specified arrays of Objects are
equal
to one another. 
static boolean 
equals
(short[] a, short[] a2)
Returns
true
if the two specified arrays of shorts are
equal
to one another. 
static void 
fill
(boolean[] a, boolean val)
Assigns the specified boolean value to each element of the specified array of booleans. 
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. 
static void 
fill
(byte[] a, byte val)
Assigns the specified byte value to each element of the specified array of bytes. 
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. 
static void 
fill
(char[] a, char val)
Assigns the specified char value to each element of the specified array of chars. 
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. 
static void 
fill
(double[] a, double val)
Assigns the specified double value to each element of the specified array of doubles. 
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. 
static void 
fill
(float[] a, float val)
Assigns the specified float value to each element of the specified array of floats. 
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. 
static void 
fill
(int[] a, int val)
Assigns the specified int value to each element of the specified array of ints. 
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. 
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. 
static void 
fill
(long[] a, long val)
Assigns the specified long value to each element of the specified array of longs. 
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. 
static void 
fill
(
Object
[] a,
Object
val)
Assigns the specified Object reference to each element of the specified array of Objects. 
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. 
static void 
fill
(short[] a, short val)
Assigns the specified short value to each element of the specified array of shorts. 
static int

hashCode
(boolean[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(byte[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(char[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(double[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(float[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(int[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(long[] a)
Returns a hash code based on the contents of the specified array.

static int

hashCode
(
Object
Returns a hash code based on the contents of the specified array.

static int

hashCode
(short[] a)
Returns a hash code based on the contents of the specified array.

static void 
sort
(byte[] a)
Sorts the specified array of bytes into ascending numerical order. 
static void 
sort
(byte[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of bytes into ascending numerical order. 
static void 
sort
(char[] a)
Sorts the specified array of chars into ascending numerical order. 
static void 
sort
(char[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of chars into ascending numerical order. 
static void 
sort
(double[] a)
Sorts the specified array of doubles into ascending numerical order. 
static void 
sort
(double[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of doubles into ascending numerical order. 
static void 
sort
(float[] a)
Sorts the specified array of floats into ascending numerical order. 
static void 
sort
(float[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of floats into ascending numerical order. 
static void 
sort
(int[] a)
Sorts the specified array of ints into ascending numerical order. 
static void 
sort
(int[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of ints into ascending numerical order. 
static void 
sort
(long[] a)
Sorts the specified array of longs into ascending numerical order. 
static void 
sort
(long[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of longs into ascending numerical order. 
static void 
sort
(
Object
[] a)
Sorts the specified array of objects into ascending order, according to the
natural ordering
of its elements. 
static void

sort
(
Object
[] a,
Comparator
Sorts the specified array of objects according to the order induced by the specified comparator.

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. 
static void

sort
(
Object
[] a, int fromIndex, int toIndex,
Comparator
Sorts the specified range of the specified array of objects according to the order induced by the specified comparator.

static void 
sort
(short[] a)
Sorts the specified array of shorts into ascending numerical order. 
static void 
sort
(short[] a, int fromIndex, int toIndex)
Sorts the specified range of the specified array of shorts into ascending numerical order. 
static
<T> void


sort
(T[] a,
Comparator
<? super T> c)
Sorts the specified array of objects according to the order induced by the specified comparator.

static
<T> void


sort
(T[] a, int fromIndex, int toIndex,
Comparator
<? super T> c)
Sorts the specified range of the specified array of objects according to the order induced by the specified comparator.

static
String

toString
(boolean[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(byte[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(char[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(double[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(float[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(int[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(long[] a)
Returns a string representation of the contents of the specified array.

static
String

toString
(
Object
Returns a string representation of the contents of the specified array.

static
String

toString
(short[] a)
Returns a string representation of the contents of the specified array.

Methods inherited from class java.lang.
Object

clone
,
equals
,
finalize
,
getClass
,
hashCode
,
notify
,
notifyAll
,
toString
,
wait
,
wait
,
wait

sort
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", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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.)
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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.)
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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.)
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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.)
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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 floatingpoint 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 floatingpoint 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(java.lang.Double)
. 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 floatingpoint value. For the purposes of sorting, all NaN values are considered equivalent and equal.
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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.)
The < relation does not provide a total order on all floatingpoint 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 floatingpoint 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(java.lang.Double)
. 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 floatingpoint value. For the purposes of sorting, all NaN values are considered equivalent and equal.
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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 floatingpoint 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 floatingpoint 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(java.lang.Float)
. 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 floatingpoint value. For the purposes of sorting, all NaN values are considered equivalent and equal.
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

a  the array to be sorted.
sort
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.)
The < relation does not provide a total order on all floatingpoint 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 floatingpoint 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(java.lang.Float)
. 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 floatingpoint value. For the purposes of sorting, all NaN values are considered equivalent and equal.
The sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", SoftwarePractice and Experience, Vol. 23(11) P. 12491265 (November 1993). This algorithm offers n*log(n) performance on many data sets that cause other quicksorts to degrade to quadratic performance.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
sort
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.


Parameters:

a  the array to be sorted.

Throws:

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

See Also:

Comparable
sort
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.


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length

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

See Also:

Comparable
sort
public static <T> void sort(T[] a,
Comparator( Object<? super T> c) [] 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.
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.


Parameters:

a  the array 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.

See Also:

Comparator
sort
public static <T> void sort(T[] a,
int fromIndex,
int toIndex,
Comparator( Object<? super T> c) [] 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.


Parameters:

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.

IllegalArgumentException
 if
fromIndex > toIndex

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length

See Also:

Comparator
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(long[])
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(int[])
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(short[])
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(char[])
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(byte[])
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(double[])
binarySearch
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
method, above) 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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.

See Also:

sort(float[])
binarySearch
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
Sort(Object[]
), above) 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 order 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.


Parameters:

a  the array to be searched.

key  the value to be searched for.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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 in not comparable to the elements of the array.

See Also:

Comparable
,
sort(Object[])
binarySearch
public static <T> int binarySearch(T[] a,
T key,
Comparator( Object<? super T> c) [] 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(Object[], Comparator)
method, above), 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.


Parameters:

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.

Returns:

index of the search key, if it is contained in the list; otherwise,
((
insertion point
)  1)
. The
insertion point
is defined as the point at which the key would be inserted into the list: the index of the first element greater than the key, or
list.size()
, if all elements in the list 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 in not mutually comparable with the elements of the array using this comparator.

See Also:

Comparable
,
sort(Object[], Comparator)
sort(Object[], Comparator)
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
equals
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.)


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.

See Also:

Double.equals(Object)
equals
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.)


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.

See Also:

Float.equals(Object)
equals
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
.


Parameters:

a  one array to be tested for equality.

a2  the other array to be tested for equality.

Returns:

true
if the two arrays are equal.
fill
public static void fill(long[] a,
long val)

Assigns the specified long value to each element of the specified array of longs.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(int[] a,
int val)

Assigns the specified int value to each element of the specified array of ints.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(short[] a,
short val)

Assigns the specified short value to each element of the specified array of shorts.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(char[] a,
char val)

Assigns the specified char value to each element of the specified array of chars.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(byte[] a,
byte val)

Assigns the specified byte value to each element of the specified array of bytes.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(boolean[] a,
boolean val)

Assigns the specified boolean value to each element of the specified array of booleans.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(double[] a,
double val)

Assigns the specified double value to each element of the specified array of doubles.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(float[] a,
float val)

Assigns the specified float value to each element of the specified array of floats.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
fill
public static void fill(Object[] a,
Object val)

Assigns the specified Object reference to each element of the specified array of Objects.


Parameters:

a  the array to be filled.

val  the value to be stored in all elements of the array.
fill
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.)


Parameters:

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

ArrayIndexOutOfBoundsException
 if
fromIndex < 0
or
toIndex > a.length
asList
public static <T> List<T> asList(T[] a) ( Object[] a)

Returns a fixedsize list backed by the specified array. (Changes to the returned list "write through" to the array.) This method acts as bridge between arraybased and collectionbased APIs, in combination with
Collection.toArray
. The returned list is serializable and implements
RandomAccess
.


Parameters:

a  the array by which the list will be backed.

Returns:

a list view of the specified array.

See Also:

Collection.toArray()
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
public static int hashCode (int[] a)

Returns a hash code based on the contents of the specified array. For any two nonnull
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose hash value to compute

Returns:

a contentbased hash code for
a

Since:

1.5
hashCode
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.


Parameters:

the  array whose contentbased hash code to compute

Returns:

a contentbased hash code for
a

Since:

1.5

See Also:

deepHashCode(Object[])
deepHashCode
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.


Parameters:

the  array whose deepcontentbased hash code to compute

Returns:

a deepcontentbased hash code for
a

Since:

1.5

See Also:

hashCode(Object[])
deepEquals
public static boolean deepEquals ( Object[] a1,
Object[] a2)

Returns
true
if the two specified arrays are
deeply equal
to one another. Unlike the @link{#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.


Parameters:

a1  one array to be tested for equality

a2  the other array to be tested for equality

Returns:

true
if the two arrays are equal

Since:

1.5

See Also:

equals(Object[],Object[])
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString (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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5
toString
public static StringtoString ( 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.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5

See Also:

#deepToString()
deepToString
public static StringdeepToString ( 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 selfreference 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
.


Parameters:

the  array whose string representation to return

Returns:

a string representation of
a

Since:

1.5

See Also:

toString(Object[])