//Instrument.java
              abstract class Instrument {
              public abstract void play();
              
              public abstract void tune();
              }
              //Glockenspiel.java
              class Glockenspiel extends
              Instrument {
              @Override public void play() {
              System.out.println("Glockenspiel: Playing the notes on the metal bars.");
              }
              
              @Override
              public void tune() {
              System.out.println("Glockenspiel: Tuning the metal bars to the correct pitch.");
              }
              }
              //Violin.java
              class Violin extends Instrument {
              @Override
              public void play() {
              System.out.println("Violin: Playing the strings with a bow or fingers.");
              }
              
              @Override
              public void tune() {
              System.out.println("Violin: Tuning the strings to the correct pitch.");
              }
              }
              //Main.java
              class Inheritance_23 {
              public static void main(String[] args) {
              Instrument glockenspiel = new Glockenspiel();
              Instrument violin = new Violin();
              
              glockenspiel.play();
              glockenspiel.tune();
              
              violin.play();
              violin.tune();
              }
              }