类 Arrays

1、继承关系：

java.lang.Object  java.util.Arrays

2、Arrays类包含了操作数组对多种方法(如排序和查找)。该类还包含了一个静态的工厂，其功能是：允许数组以列表形式展示。

3、如果指定数组是null，该类允许跑出空指针异常( NullPointerException)，除非特别声明。

4、Arrays类中包含的方法的文本说明包括其实现的简要介绍。这些描述应该被认作是实现说明，而不是规范。

5、实现算法可以随意替代其它算法，只要要求本身是一致的。(例如，sort(Object)使用的算法未必一定得是归并排序算法，而且算法也不一定是稳定算法才行。)

6、方法概要：

Method Summarystatic<T> List<T>asList(T... a) 
          Returns a fixed-size list backed by the specified array.static intbinarySearch(byte[] a, byte key) 
          Searches the specified array of bytes for the specified value using the binary search algorithm.static intbinarySearch(byte[] a, int fromIndex, int toIndex, byte key) 
          Searches a range of the specified array of bytes for the specified value using the binary search algorithm.static intbinarySearch(char[] a, char key) 
          Searches the specified array of chars for the specified value using the binary search algorithm.static intbinarySearch(char[] a, int fromIndex, int toIndex, char key) 
          Searches a range of the specified array of chars for the specified value using the binary search algorithm.static intbinarySearch(double[] a, double key) 
          Searches the specified array of doubles for the specified value using the binary search algorithm.static intbinarySearch(double[] a, int fromIndex, int toIndex, double key) 
          Searches a range of the specified array of doubles for the specified value using the binary search algorithm.static intbinarySearch(float[] a, float key) 
          Searches the specified array of floats for the specified value using the binary search algorithm.static intbinarySearch(float[] a, int fromIndex, int toIndex, float key) 
          Searches a range of the specified array of floats for the specified value using the binary search algorithm.static intbinarySearch(int[] a, int key) 
          Searches the specified array of ints for the specified value using the binary search algorithm.static intbinarySearch(int[] a, int fromIndex, int toIndex, int key) 
          Searches a range of the specified array of ints for the specified value using the binary search algorithm.static intbinarySearch(long[] a, int fromIndex, int toIndex, long key) 
          Searches a range of the specified array of longs for the specified value using the binary search algorithm.static intbinarySearch(long[] a, long key) 
          Searches the specified array of longs for the specified value using the binary search algorithm.static intbinarySearch(Object[] a, int fromIndex, int toIndex, Object key) 
          Searches a range of the specified array for the specified object using the binary search algorithm.static intbinarySearch(Object[] a, Object key) 
          Searches the specified array for the specified object using the binary search algorithm.static intbinarySearch(short[] a, int fromIndex, int toIndex, short key) 
          Searches a range of the specified array of shorts for the specified value using the binary search algorithm.static intbinarySearch(short[] a, short key) 
          Searches the specified array of shorts for the specified value using the binary search algorithm.static<T> intbinarySearch(T[] a, int fromIndex, int toIndex, T key, Comparator<? super T> c) 
          Searches a range of the specified array for the specified object using the binary search algorithm.static<T> intbinarySearch(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<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.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.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<T> T[]copyOfRange(T[] original, int from, int to) 
          Copies the specified range of the specified array into a new array.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.static booleandeepEquals(Object[] a1, Object[] a2) 
          Returns true if the two specified arrays are deeply equal to one another.static intdeepHashCode(Object[] a) 
          Returns a hash code based on the "deep contents" of the specified array.static StringdeepToString(Object[] a) 
          Returns a string representation of the "deep contents" of the specified array.static booleanequals(boolean[] a, boolean[] a2) 
          Returns true if the two specified arrays of booleans are equal to one another.static booleanequals(byte[] a, byte[] a2) 
          Returns true if the two specified arrays of bytes are equal to one another.static booleanequals(char[] a, char[] a2) 
          Returns true if the two specified arrays of chars are equal to one another.static booleanequals(double[] a, double[] a2) 
          Returns true if the two specified arrays of doubles are equal to one another.static booleanequals(float[] a, float[] a2) 
          Returns true if the two specified arrays of floats are equal to one another.static booleanequals(int[] a, int[] a2) 
          Returns true if the two specified arrays of ints are equal to one another.static booleanequals(long[] a, long[] a2) 
          Returns true if the two specified arrays of longs are equal to one another.static booleanequals(Object[] a, Object[] a2) 
          Returns true if the two specified arrays of Objects are equal to one another.static booleanequals(short[] a, short[] a2) 
          Returns true if the two specified arrays of shorts are equal to one another.static voidfill(boolean[] a, boolean val) 
          Assigns the specified boolean value to each element of the specified array of booleans.static voidfill(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 voidfill(byte[] a, byte val) 
          Assigns the specified byte value to each element of the specified array of bytes.static voidfill(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 voidfill(char[] a, char val) 
          Assigns the specified char value to each element of the specified array of chars.static voidfill(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 voidfill(double[] a, double val) 
          Assigns the specified double value to each element of the specified array of doubles.static voidfill(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 voidfill(float[] a, float val) 
          Assigns the specified float value to each element of the specified array of floats.static voidfill(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 voidfill(int[] a, int val) 
          Assigns the specified int value to each element of the specified array of ints.static voidfill(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 voidfill(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 voidfill(long[] a, long val) 
          Assigns the specified long value to each element of the specified array of longs.static voidfill(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 voidfill(Object[] a, Object val) 
          Assigns the specified Object reference to each element of the specified array of Objects.static voidfill(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 voidfill(short[] a, short val) 
          Assigns the specified short value to each element of the specified array of shorts.static inthashCode(boolean[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(byte[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(char[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(double[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(float[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(int[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(long[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(Object[] a) 
          Returns a hash code based on the contents of the specified array.static inthashCode(short[] a) 
          Returns a hash code based on the contents of the specified array.static voidsort(byte[] a) 
          Sorts the specified array of bytes into ascending numerical order.static voidsort(byte[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of bytes into ascending numerical order.static voidsort(char[] a) 
          Sorts the specified array of chars into ascending numerical order.static voidsort(char[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of chars into ascending numerical order.static voidsort(double[] a) 
          Sorts the specified array of doubles into ascending numerical order.static voidsort(double[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of doubles into ascending numerical order.static voidsort(float[] a) 
          Sorts the specified array of floats into ascending numerical order.static voidsort(float[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of floats into ascending numerical order.static voidsort(int[] a) 
          Sorts the specified array of ints into ascending numerical order.static voidsort(int[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of ints into ascending numerical order.static voidsort(long[] a) 
          Sorts the specified array of longs into ascending numerical order.static voidsort(long[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of longs into ascending numerical order.static voidsort(Object[] a) 
          Sorts the specified array of objects into ascending order, according to the natural ordering of its elements.static voidsort(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 voidsort(short[] a) 
          Sorts the specified array of shorts into ascending numerical order.static voidsort(short[] a, int fromIndex, int toIndex) 
          Sorts the specified range of the specified array of shorts into ascending numerical order.static<T> voidsort(T[] a, Comparator<? super T> c) 
          Sorts the specified array of objects according to the order induced by the specified comparator.static<T> voidsort(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 StringtoString(boolean[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(byte[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(char[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(double[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(float[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(int[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(long[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(Object[] a) 
          Returns a string representation of the contents of the specified array.static StringtoString(short[] a) 
          Returns a string representation of the contents of the specified array. Methods inherited from class java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait