package com.example.foo;

import java.lang.reflect.Field;

public class SomeClass {
  public static void main(final String[] args) throws Throwable {
    final String s = "Umesh";
    changeString(s);
  }

  // We need a method so the compiler won't inline "s":
  static void changeString(final String s) throws Throwable {

    System.out.println("Original: " + s);
    final Field field = String.class.getDeclaredField("value");
    field.setAccessible(true);
    final char[] value = (char[]) field.get(s);
    value[0] = 'X';
    System.out.println("Changed: " + s);
  }
}