String 引用于地址

package interview;

public class TestString {
public static void main(String[] args) {
    //"abc"在字符串库中没有abc 的情况下是相当与new String () +  赋值= 两个过程
    //但是字符串库中存在abc 时候是就没有new String () 这过程；
    String s1 = "abc";
    String s2 = "abc";

    int i = s1.hashCode();
    int i1 = s2.hashCode();
    System.out.println(i + "\t" + i1);

    String s3 = new String("abc");
    String s4 = new String("abc");
    int j1 = s3.hashCode();
    int j2 = s4.hashCode();
    System.out.println(j1 + "\t" + j2);
    System.out.println(s3.hashCode());
    System.out.println(System.identityHashCode(s3));
    System.out.println(System.identityHashCode(s4));
    System.out.println(System.identityHashCode(s1));
    System.out.println(System.identityHashCode(s2));

}}