/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.lang.reflect.Field;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone {
 
	public static void main(String[] args) throws Exception {
        final String hello = "Hello World!";
        describe(hello);
        mutateString(hello, "Goodbye World!");
        describe(hello);
    }
 
    private static void mutateString(String object, String newContent) throws Exception {
        final Field f = String.class.getDeclaredField("value");
        f.setAccessible(true);
        f.set(object, newContent.toCharArray());
    }
 
    private static void describe(String object) {
        System.out.println(System.identityHashCode(object) + " " + object);
    }
}

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