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