arrays.java

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        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (a1[i] != a2[i])
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two char arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a2 is of the same length
   *         as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
   */
  public static boolean equals(char[] a1, char[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (a1[i] != a2[i])
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two short arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a2 is of the same length
   *         as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
   */
  public static boolean equals(short[] a1, short[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (a1[i] != a2[i])
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two int arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a2 is of the same length
   *         as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
   */
  public static boolean equals(int[] a1, int[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (a1[i] != a2[i])
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two long arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a2 is of the same length
   *         as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
   */
  public static boolean equals(long[] a1, long[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (a1[i] != a2[i])
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two float arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a2 is of the same length
   *         as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
   */
  public static boolean equals(float[] a1, float[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    // Must use Float.compare to take into account NaN, +-0.
    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (Float.compare(a1[i], a2[i]) != 0)
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two double arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a2 is of the same length
   *         as a1, and for each 0 <= i < a1.length, a1[i] == a2[i]
   */
  public static boolean equals(double[] a1, double[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    // Must use Double.compare to take into account NaN, +-0.
    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (Double.compare(a1[i], a2[i]) != 0)
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }

  /**
   * Compare two Object arrays for equality.
   *
   * @param a1 the first array to compare
   * @param a2 the second array to compare
   * @return true if a1 and a2 are both null, or if a1 is of the same length
   *         as a2, and for each 0 <= i < a.length, a1[i] == null ?
   *         a2[i] == null : a1[i].equals(a2[i]).
   */
  public static boolean equals(Object[] a1, Object[] a2)
  {
    // Quick test which saves comparing elements of the same array, and also
    // catches the case that both are null.
    if (a1 == a2)
      return true;

    try
      {
        // If they're the same length, test each element
        if (a1.length == a2.length)
          {
            int i = a1.length;
            while (--i >= 0)
              if (! AbstractCollection.equals(a1[i], a2[i]))
                return false;
            return true;
          }
      }
    catch (NullPointerException e)
      {
        // If one is null, we get a harmless NullPointerException
      }
    return false;
  }


// fill
  /**
   * Fill an array with a boolean value.
   *
   * @param a the array to fill
   * @param val the value to fill it with
   */
  public static void fill(boolean[] a, boolean val)
  {
    fill(a, 0, a.length, val);
  }

  /**
   * Fill a range of an array with a boolean value.
   *
   * @param a the array to fill
   * @param fromIndex the index to fill from, inclusive
   * @param toIndex the index to fill to, exclusive
   * @param val the value to fill with
   * @throws IllegalArgumentException if fromIndex &gt; toIndex
   * @throws ArrayIndexOutOfBoundsException if fromIndex &lt; 0
   *         || toIndex &gt; a.length
   */
  public static void fill(boolean[] a, int fromIndex, int toIndex, boolean val)
  {
    if (fromIndex > toIndex)
      throw new IllegalArgumentException();
    for (int i = fromIndex; i < toIndex; i++)
      a[i] = val;
  }

  /**
   * Fill an array with a byte value.
   *
   * @param a the array to fill
   * @param val the value to fill it with
   */
  public static void fill(byte[] a, byte val)
  {
    fill(a, 0, a.length, val);
  }

  /**
   * Fill a range of an array with a byte value.
   *
   * @param a the array to fill
   * @param fromIndex the index to fill from, inclusive
   * @param toIndex the index to fill to, exclusive
   * @param val the value to fill with
   * @throws IllegalArgumentException if fromIndex &gt; toIndex
   * @throws ArrayIndexOutOfBoundsException if fromIndex &lt; 0
   *         || toIndex &gt; a.length
   */
  public static void fill(byte[] a, int fromIndex, int toIndex, byte val)
  {
    if (fromIndex > toIndex)
      throw new IllegalArgumentException();
    for (int i = fromIndex; i < toIndex; i++)
      a[i] = val;
  }

  /**
   * Fill an array with a char value.
   *
   * @param a the array to fill
   * @param val the value to fill it with
   */
  public static void fill(char[] a, char val)
  {
    fill(a, 0, a.length, val);
  }

  /**
   * Fill a range of an array with a char value.
   *
   * @param a the array to fill
   * @param fromIndex the index to fill from, inclusive
   * @param toIndex the index to fill to, exclusive
   * @param val the value to fill with
   * @throws IllegalArgumentException if fromIndex &gt; toIndex
   * @throws ArrayIndexOutOfBoundsException if fromIndex &lt; 0
   *         || toIndex &gt; a.length
   */
  public static void fill(char[] a, int fromIndex, int toIndex, char val)
  {
    if (fromIndex > toIndex)
      throw new IllegalArgumentException();
    for (int i = fromIndex; i < toIndex; i++)
      a[i] = val;
  }

  /**
   * Fill an array with a short value.
   *
   * @param a the array to fill
   * @param val the value to fill it with
   */
  public static void fill(short[] a, short val)
  {
    fill(a, 0, a.length, val);
  }

  /**
   * Fill a range of an array with a short value.
   *
   * @param a the array to fill
   * @param fromIndex the index to fill from, inclusive
   * @param toIndex the index to fill to, exclusive
   * @param val the value to fill with
   * @throws IllegalArgumentException if fromIndex &gt; toIndex
   * @throws ArrayIndexOutOfBoundsException if fromIndex &lt; 0
   *         || toIndex &gt; a.length
   */
  public static void fill(short[] a, int fromIndex, int toIndex, short val)
  {
    if (fromIndex > toIndex)
      throw new IllegalArgumentException();
    for (int i = fromIndex; i < toIndex; i++)
      a[i] = val;
  }

  /**
   * Fill an array with an int value.
   *
   * @param a the array to fill
   * @param val the value to fill it with
   */
  public static void fill(int[] a, int val)
  {
    fill(a, 0, a.length, val);
  }

  /**
   * Fill a range of an array with an int value.
   *
   * @param a the array to fill
   * @param fromIndex the index to fill from, inclusive
   * @param toIndex the index to fill to, exclusive
   * @param val the value to fill with
   * @throws IllegalArgumentException if fromIndex &gt; toIndex
   * @throws ArrayIndexOutOfBoundsException if fromIndex &lt; 0
   *         || toIndex &gt; a.length
   */
  public static void fill(int[] a, int fromIndex, int toIndex, int val)
  {
    if (fromIndex > toIndex)
      throw new IllegalArgumentException();
    for (int i = fromIndex; i < toIndex; i++)
      a[i] = val;
  }

  /**
   * Fill an array with a long value.
   *
   * @param a the array to fill
   * @param val the value to fill it with
   */
  public static void fill(long[] a, long val)
  {
    fill(a, 0, a.length, val);
  }

  /**
   * Fill a range of an array with a long value.
   *
   * @param a the array to fill
   * @param fromIndex the index to fill from, inclusive
   * @param toIndex the index to fill to, exclusive
   * @param val the value to fill with
   * @throws IllegalArgumentException if fromIndex &gt; toIndex
   * @throws ArrayIndexOutOfBoundsException if fromIndex &lt; 0
   *         || toIndex &gt; a.length
   */
  public static void fill(long[] a, int fromIndex, int toIndex, long val)
  {
    if (fromIndex > toIndex)
      throw new IllegalArgumentException();
    for (int i = fromIndex; i < toIndex; i++)