is new.
java.lang.Objectjava.util.Arrays
public class Arrays
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 .
| Method Summary | ||
|---|---|---|
static
|
asList
(T... a) Returns a fixed-size 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
(short[] a, short key) Searches the specified array of shorts for the specified value using the binary search algorithm. |
|
static
|
binarySearch
(T[] a, T key,
Comparator
<? super T> c) Searches the specified array for the specified object using the binary search algorithm. |
|
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.
|
|
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.
|
|
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.
|
|
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.
|
|
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.
|
|
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.
|
|
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.
|
|
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.
|
|
static
|
copyOf
(T[] original, int newLength)
Copies the specified array, truncating or padding with nulls (if necessary) so the copy has the specified length.
|
|
static
|
copyOf
(U[] original, int newLength,
Class
<? extends T[]> newType)
Copies the specified array, truncating or padding with nulls (if necessary) so the copy has the specified length.
|
|
static boolean[]
|
copyOfRange
(boolean[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static byte[]
|
copyOfRange
(byte[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static char[]
|
copyOfRange
(char[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static double[]
|
copyOfRange
(double[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static float[]
|
copyOfRange
(float[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static int[]
|
copyOfRange
(int[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static long[]
|
copyOfRange
(long[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static short[]
|
copyOfRange
(short[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static
|
copyOfRange
(T[] original, int from, int to)
Copies the specified range of the specified array into a new array.
|
|
static
|
copyOfRange
(U[] original, int from, int to,
Class
<? extends T[]> newType)
Copies the specified range of the specified array into a new array.
|
|
| static boolean |
deepEquals
(
Object
[] a1,
Object
[] a2) Returns true if the two specified arrays are deeply equal to one another. |
|
| static int |
deepHashCode
(
Object
[] a) Returns a hash code based on the "deep contents" of the specified array. |
|
| static String |
deepToString
(
Object
[] a) 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
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
[] a) 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, 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
(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
|
sort
(T[] a,
Comparator
<? super T> c) Sorts the specified array of objects according to the order induced by the specified comparator. |
|
static
|
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
[] a) 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 |
| Method Detail |
|---|
public static void sort(long[] a)
public static void sort(long[] a,
int fromIndex,
int toIndex)
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.
public static void sort(int[] a)
public static void sort(int[] a,
int fromIndex,
int toIndex)
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.
public static void sort(short[] a)
public static void sort(short[] a,
int fromIndex,
int toIndex)
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.
public static void sort(char[] a)
public static void sort(char[] a,
int fromIndex,
int toIndex)
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.
public static void sort(byte[] a)
public static void sort(byte[] a,
int fromIndex,
int toIndex)
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.
public static void sort(double[] a)
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(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 floating-point 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", 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.
public static void sort(double[] a,
int fromIndex,
int toIndex)
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(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 floating-point 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", 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.
public static void sort(float[] a)
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(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 floating-point 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", 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.
public static void sort(float[] a,
int fromIndex,
int toIndex)
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(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 floating-point 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", 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.
public static void sort(Object[] a)
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.
public static void sort(Object[] a,
int fromIndex,
int toIndex)
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.
public static <T> void sort(T[] a,
Comparator<? super T> c)
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.
public static <T> void sort(T[] a,
int fromIndex,
int toIndex,
Comparator<? super T> c)
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.
public static int binarySearch(long[] a,
long key)
array;
array:
a.length
array
public static int binarySearch(int[] a,
int key)
array;
array:
a.length
array
public static int binarySearch(short[] a,
short key)
array;
array:
a.length
array
public static int binarySearch(char[] a,
char key)
array;
array:
a.length
array
public static int binarySearch(byte[] a,
byte key)
array;
array:
a.length
array
public static int binarySearch(double[] a,
double key)
array;
array:
a.length
array
public static int binarySearch(float[] a,
float key)
array;
array:
a.length
array
public static int binarySearch(Object[] a,
Object key)
array;
array:
a.length
array
public static <T> int binarySearch(T[] a,
T key,
Comparator<? super T> c)
array;
array:
a.length
array
public static boolean equals(long[] a,
long[] a2)
public static boolean equals(int[] a,
int[] a2)
public static boolean equals(short[] a,
short[] a2)
public static boolean equals(char[] a,
char[] a2)
public static boolean equals(byte[] a,
byte[] a2)
public static boolean equals(boolean[] a,
boolean[] a2)
public static boolean equals(double[] a,
double[] a2)
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.)
public static boolean equals(float[] a,
float[] a2)
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.)
public static boolean equals(Object[] a,
Object[] a2)
public static void fill(long[] a,
long val)
public static void fill(long[] a,
int fromIndex,
int toIndex,
long val)
public static void fill(int[] a,
int val)
public static void fill(int[] a,
int fromIndex,
int toIndex,
int val)
public static void fill(short[] a,
short val)
public static void fill(short[] a,
int fromIndex,
int toIndex,
short val)
public static void fill(char[] a,
char val)
public static void fill(char[] a,
int fromIndex,
int toIndex,
char val)
public static void fill(byte[] a,
byte val)
public static void fill(byte[] a,
int fromIndex,
int toIndex,
byte val)
public static void fill(boolean[] a,
boolean val)
public static void fill(boolean[] a,
int fromIndex,
int toIndex,
boolean val)
public static void fill(double[] a,
double val)
public static void fill(double[] a,
int fromIndex,
int toIndex,
double val)
public static void fill(float[] a,
float val)
public static void fill(float[] a,
int fromIndex,
int toIndex,
float val)
public static void fill(Object[] a,
Object val)
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)
ArrayStoreException
- if the specified value is not of a runtime type that can be stored in the specified array
copyOf
public static <T> T[]
copyOf
(T[] 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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with nulls to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
public static <T,U> T[]
copyOf
(U[] original, int newLength,
Class
<? extends T[]> 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
.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
newType - the class of the copy to be returned
Returns:
a copy of the original array, truncated or padded with nulls to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
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
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with null characters to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with zeros to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOf
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.
Parameters:
original - the array to be copied
newLength - the length of the copy to be returned
Returns:
a copy of the original array, truncated or padded with false elements to obtain the specified length
Throws:
NegativeArraySizeException
- if
newLength
is negative
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
public static <T> T[]
copyOfRange
(T[] 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.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
public static <T,U> T[]
copyOfRange
(U[] original, int from, int to,
Class
<? extends T[]> 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
.
Parameters:
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
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
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
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
copyOfRange
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
.
Parameters:
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.)
Returns:
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()
IllegalArgumentException
- if
from > to
NullPointerException
- if
original
is null
Since:
1.6
public static <T> List<T> asList(T... a)
Collection.toArray()
This method also provides a convenient way to create a fixed-size list initialized to contain several elements:
List<String>
Liststooges = Arrays.asList("Larry", "Moe", "Curly");
backed
array
public static int hashCode(long[] a)
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.
public static int hashCode(int[] a)
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.
public static int hashCode(short[] a)
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.
public static int hashCode(char[] a)
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.
public static int hashCode(byte[] a)
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.
public static int hashCode(boolean[] a)
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.
public static int hashCode(float[] a)
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.
public static int hashCode(double[] a)
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.
public static int hashCode(Object[] a)
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.
public static int deepHashCode(Object[] a)
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.
public static boolean deepEquals(Object[] a1,
Object[] a2)
equals(Object[],Object[])
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:
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.
public static String toString(long[] a)
public static String toString(int[] a)
public static String toString(short[] a)
public static String toString(char[] a)
public static String toString(byte[] a)
public static String toString(boolean[] a)
public static String toString(float[] a)
public static String toString(double[] a)
public static String toString(Object[] a)
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.
public static String deepToString(Object[] a)
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 .