修改openjdk17 java/lang/String.java 类源码，增加一个native本地方法打印固定字符串功能

java/lang/String.java 新增加native方法

public native void printStringTable();

##图片

##/home/yym/openjdk17/jdk17-master/src/hotspot/share/include/jvm.h文件增加方法

//yym-gaizao
JNIEXPORT void JNICALL
JVM_String_printStringTable(JNIEnv *env, jstring str);

##src/hotspot/share/prims/jvm.cpp文件增加方法

//yym-gaizao
JVM_ENTRY(void, JVM_String_printStringTable(JNIEnv *env, jstring str))
  std::cout << "@@@@yym%%%%method address " << "" << "----begin" << std::endl;
  
JVM_END

##/home/yym/openjdk17/jdk17-master/build/linux-x86_64-server-slowdebug/support/headers/java.base/java_lang_String.h增加方法

//yym-gaizao
/*
 * Class:     java_lang_String
 * Method:    printStringTable
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_java_lang_String_printStringTable
  (JNIEnv *, jobject);

##src/java.base/share/native/libjava/String.c增加方法

//yym-gaizao
JNIEXPORT void JNICALL
Java_java_lang_String_printStringTable(JNIEnv *env, jobject this)
{
    JVM_String_printStringTable(env, this);
}

##/home/yym/openjdk17/jdk17-master/make/data/hotspot-symbols/symbols-unix符号表增加JVM_String_printStringTable方法符号

# yym-gaizao
JVM_String_printStringTable

##编译openjdk17源码

yym@yym:~/javaTest$ cd /home/yym/openjdk17/jdk17-master/
yym@yym:~/openjdk17/jdk17-master$ make CONF=linux-x86_64-server-slowdebug

##编写编译StringTableMain.java类并运行

yym@yym:~/javaTest$ /home/yym/openjdk17/jdk17-master/build/linux-x86_64-server-slowdebug/jdk/bin/javac StringTableMain.java
yym@yym:~/javaTest$ /home/yym/openjdk17/jdk17-master/build/linux-x86_64-server-slowdebug/jdk/bin/java StringTableMain
@@@@yym%%%%method address ----begin
------------------------------------
yyyyyyyyyyyyyyyyy
ddddddddddddddddddddddddddddddd
yym@yym:~/javaTest$ cat StringTableMain.java
public class StringTableMain {

    public static final String yyyyyyyyyyyyyyyyy="yyyyyyyyyyyyyyyyy";

    public static void main(String[] args) {
        "-----------yym----------".intern();
        "-----------ddd----------".printStringTable();
        String ddddddddddddddddddddddddddddddd="ddddddddddddddddddddddddddddddd";
        System.out.println("------------------------------------");
        System.out.println(yyyyyyyyyyyyyyyyy);
        System.out.println(ddddddddddddddddddddddddddddddd);
    }

}