CONSTANT_String_info{

    u1 tag=8;

    u2 string_index;//存放 CONSTANT_Utf8_info 指针

}

CONSTANT_Utf8_info{

　　u1 tag=1;

　　u2 length;//字节数组长度

　　u1 bytes[length];//使用utf8编码后的字节数组

}

public class StringDemo {

    private String s1="字符串S1";

}

CONSTANT_Utf8_info{

    u1 tag=1;

    u2 length;//字节数组长度

    u1 bytes[length];//使用utf8编码后的字节数组

}

CONSTANT_String_info{

    u1 tag=8;

    u2 string_index;//存放#15

}

public class StringDemo {

    private String s1="MyStr1";

    private String s2="MyStr1";

}

public class StringDemo {

    private String s1= new String("MyStr1");

}

public class StringDemo20 {

    private String s1="MyStr1";

    private String s2="MyStr1";

    private String s3="My"+"Str1";

    private String s01="My";

    private String s02="Str1";

    private String s4 = s01+s02;

    private String s5 = s4.intern();

    private static String str1="MyStr1";

    private static String str2="MyStr1";

    private static String str3="My"+"Str1";

    private static String str01="My";

    private static String str02="Str1";

    private static String str4 = str01+str02;

    private static String str5 = str4.intern();

    private static final String fstr1="MyStr1";

    private static final String fstr2="MyStr1";

    private static final String fstr3="My"+"Str1";

    private static final String fstr01="My";

    private static final String fstr02="Str1";

    private static final String fstr4 = fstr01+fstr02;

    private static final String fstr5 = fstr4.intern();

    class InnerDemo{

        private String s1="MyStr1";

        private String s2="MyStr1";

        private String s3="My"+"Str1";

        private String s01="My";

        private String s02="Str1";

        private String s4 = s01+s02;

        private String s5 = s4.intern();

        private static final String ifstr1="MyStr1";

        private static final String ifstr2="MyStr1";

        private static final String ifstr3="My"+"Str1";

        private static final String ifstr01="My";

        private static final String ifstr02="Str1";

        private static final String ifstr4 = ifstr01+ifstr02;

        //private static final String ifstr5 = ifstr4.intern();

    }

    public static void main(String[] args){

        StringDemo20 stringDemo = new StringDemo20();

         System.out.println("s1==s2："+(stringDemo.s1==stringDemo.s2));

        System.out.println("s1==s3："+(stringDemo.s1==stringDemo.s3));

        System.out.println("s1==s4："+(stringDemo.s1==stringDemo.s4));//false

        System.out.println("s1==s5："+(stringDemo.s1==stringDemo.s5));

        System.out.println("s1==str1："+(stringDemo.s1==StringDemo20.str1));

        System.out.println("s1==str3："+(stringDemo.s1==StringDemo20.str3));

        System.out.println("s1==str4："+(stringDemo.s1==StringDemo20.str4));//false

        System.out.println("s1==str5："+(stringDemo.s1==StringDemo20.str5));

        System.out.println("s1==fstr1："+(stringDemo.s1==StringDemo20.fstr1));

        System.out.println("s1==fstr3："+(stringDemo.s1==StringDemo20.fstr3));

        System.out.println("s1==fstr4："+(stringDemo.s1==StringDemo20.fstr4));

        System.out.println("s1==fstr5："+(stringDemo.s1==StringDemo20.fstr5));

        System.out.println("s1==innerdemo.fstr1："+(stringDemo.s1==InnerDemo.ifstr1));

        System.out.println("s1==innerdemo.fstr3："+(stringDemo.s1==InnerDemo.ifstr3));

        System.out.println("s1==innerdemo.fstr4："+(stringDemo.s1==InnerDemo.ifstr4));

    }

}