public class ArrayCopy
{
    public static void main(String[] args)
    {
        int[] a = new int[]{1, 2, 3, 4};
        int[] b = new int[]{4};

        System.arraycopy(a, 0, b, 0, 4);

        for(int i = 0; i < b.length; i++)
        {
            System.out.print(b[i] + " ");//可编译，无法执行？？
        }
    }
}

2、

public class ThreeDimensionArrayTest
{
    public static void main(String[] args)
    {
        int[][][] a = new int[2][3][4];

        System.out.println(a instanceof int[][][]);
        System.out.println(a[0] instanceof int[][]);
        System.out.println(a[0][0] instanceof int[]);

        for(int i = 0; i < a.length; i++)
        {
            for (int j = 0; j < a[i].length; j++)
            {
                for(int k = 0; k < a[i][j].length; k++)
                {
                    a[i][j][k] = 100;
                }
            }
        }
    }
}

3、冒泡排序

public class BubbleSortTest
{
    public static void bubbleSort(int[] array)
    {
        for(int i = 0; i < array.length - 1; i++)
        {
            for(int j = 0; j < array.length - i - 1; j++)
            {
                if(array[j] > array[j + 1])
                {
                    int temp = array[j];
                    array[j] = array[j + 1];
                    array[j + 1] = temp;
                }
            }

            System.out.println("第" + (i + 1) + "趟排序");
            for(int k = 0; k < array.length; k++)
            {
                System.out.print(array[k] + " ");//第一趟排序
                                                 //4 7 3 2 8
                                                //第二趟排序
                                                //4 3 2 7 8
                                               //第三趟排序
                                              //3 2 4 7 8
                                             //第四趟排序
                                             //2 3 4 7 8
            }
            System.out.println();
        }
    }

    public static void main(String[] args)
    {
        int[] array = {4, 7, 8, 3, 2};

        bubbleSort(array);
    }

}

对比：

public class A
{
    public static void bubbleSort(int[] array)
    {
        for(int i = 0; i < array.length - 1; i++)
        {
            if(array[i] > array[i + 1])
            {
                int temp = array[i];
                array[i] = array[i + 1];
                array[i + 1] = temp;
            }

            System.out.print(array[i] + " ");//0143
        }

    }

    public static void main(String[] args)
    {
        int[] array = {1, 0, 4, 8, 3};
        
        bubbleSort(array);
    }
}

3、作业：交换排序和快速排序的原理与实现方式