Thinking in Java 第十六章学习笔记----数组

package com.testregularExpression;

import java.util.Arrays;

class BerylliumSphere {
    private static long counter;
    private final long id = counter++;
    public String toString(){ return "Sphere" + id;}
}

public class ContainerComparison {
    public static void main(String[] args){
        BerylliumSphere[] Sphere  = new BerylliumSphere[5];
        //在定义了对象数组Sphere后，编译器自动初始化值为null。
        System.out.println(Arrays.toString(Sphere));
        for(int i = 0; i < 5; i++){
            Sphere[i] = new BerylliumSphere();
        }
        //数组赋值为BerylliumSphere对象，具体值为地址。所以当要被当做String型值打印出来的时候就会自动调用toString方法。
        System.out.println(Sphere[1] + "aaa");
        System.out.println(Arrays.toString(Sphere));
    }
}