1 数组

静态初始化：创建+赋值
动态初始化：包含默认初始化

package array;

import java.lang.reflect.Array;
import java.util.Arrays;

public class Demo01 {
    public static void main(String[] args) {
        int[] a=new int[10];
        System.out.println(a);
        System.out.println(Arrays.toString(a));
        Arrays.fill(a,10);
        System.out.println(Arrays.toString(a));
        Arrays.fill(a,2,5,99);
        System.out.println(Arrays.toString(a));
    }
}

输出

[I@1b6d3586
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[10, 10, 10, 10, 10, 10, 10, 10, 10, 10]
[10, 10, 99, 99, 99, 10, 10, 10, 10, 10]

压缩数组