public class Engine {

   public String turnON() {
     return new String("turn on");
   }
}

public class Car extends Engine {

  public void drive() {
     System.out.println(this.turnON()); //it works fine because Car can inherit the public method
     
     Engine engine = new Engine();
     System.out.println(engine.turnON()); // We can invoke it on an Engine reference becuase turnON() is public
  }

}