// patterns/SingletonPattern3.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.

class MyString {
  private String s;
  public MyString(String s) {
    this.s = s;
  }
  public synchronized
  void change(String s) {
    this.s = s;
  }
  @Override public synchronized
  String toString() {
    return s;
  }
}

public class SingletonPattern3 {
  public static void main(String[] args) {
    Single<MyString> x =
      new Single<>(new MyString("Hello"));
    System.out.println(x.get());
    x.get().change("World!");
    System.out.println(x.get());
  }
}
/* Output:
Hello
World!
*/