之后重新理解这个知识点时，又写了一些小例子

String a1 = new String("str01") ;        String a2 = "str01" ;        System.out.println(a1 == a2) ;//false

String a1 = new String("str01") ;        a1.intern() ;        String a2 = "str01" ;        System.out.println(a1 == a2) ;//false

String a1 = new String("str") + new String("01") ;        String a2 = "str01" ;        System.out.println(a1 == a2) ;//fasle

String a1 = new String("str") + new String("01") ;        a1.intern() ;        String a2 = "str01" ;        System.out.println(a1 == a2) ;//true

　　　　 String s0 = "kvill" ;        String s1 = new String("kvill") ;        String s2 = new String("kvill") ;        System.out.println(s0 == s1);//false        s1.intern() ;        s2 = s2.intern() ;        System.out.println(s0 == s1) ;//false        System.out.println(s0 == s1.intern()) ;//true        System.out.println(s0 == s2) ;//true

String s1 = new String("kvill") +new String("kvill");        String s2 = s1.intern() ;        System.out.println(s2 == s1) ;//  true

String s1 = new String("kvill") +new String("kvill");        s1.intern() ;        String s2 = "kvillkvill" ;        System.out.println(s2 == s1) ;//true