Learning-design-patterns-singleton-logger.java

public class Logger {
  public void success(string message) {
    System.out.println(String.format("SUCCESS %s", message));
  }

  public void success(string message) {
    System.out.println(String.format("SUCCESS %s", message));
  }
}

public class SingletonLogger {
  private Logger instance = null;
  private Logger createInstance() {
    return new Logger();
  }
  public getInstance() {
    if(this.instance == null) {
      this.instance = this.createInstance();
    }

    return this.instance;
  }
}