CaveOfProgramming.com.Complete.Beginner.28.Interfaces

App.java

public class App{
//test
 public static void main(String[] args) {
  
Machine machine1 = new Machine();
machine1.start();

Person person1 = new Person("Lily");
person1.greet();

Info info1 = new Machine(); // Illustrate possible usage of Info Interface as a Type, like a Class
info1.showInfo(); // the created object of Type Machine is assigned to a variable of type Info, and the method in Info Interface can be called on it
  // which is really cool
}

}

Info.java

public interface Info {
  
  public void showInfo(); // Interfaces just have the header of the method, no curly brackets
}

Machine.java

public class Machine implements Info{

  @Override
  public void showInfo() {
    System.out.println("Machine ID is" + id);
    
  }

  private int id = 7;
  
  public void start(){
    System.out.println("Machine Started");
  }
}

Person.java

public class Person implements Info {
  //change 23:57
  private String name;

  public Person(String name) {
    this.name = name;
  }

  public void greet(){
    System.out.println("Greetings!");
  }

  @Override
  public void showInfo() {
    System.out.println("Person name is" + name);    
  }

  
}