### /com/in28minutes/java/oops/interfaces/Aeroplane.java

package com.in28minutes.java.oops.interfaces;

public class Aeroplane implements Flyable { public void fly() { System.out.println("Aeroplane is flying"); } }

### /com/in28minutes/java/oops/interfaces/Bird.java

package com.in28minutes.java.oops.interfaces; public class Bird implements Flyable { public void fly() { System.out.println("Bird is flying"); } }

### /com/in28minutes/java/oops/interfaces/Flyable.java

package com.in28minutes.java.oops.interfaces;

public interface Flyable { void fly(); }

### /com/in28minutes/java/oops/interfaces/IntefaceRules.java

package com.in28minutes.java.oops.interfaces;

public class IntefaceRules { }

interface ExampleInterface1 { // By default - public static final. No other modifier allowed // value1,value2,value3,value4 all are - public static final int value1 = 10; public int value2 = 15; public static int value3 = 20; public static final int value4 = 25;

// private int value5 = 10;//COMPILER ERROR

// By default - public abstract. No other modifier allowed
void method1();// method1 is public and abstract
// private void method6();//COMPILER ERROR!

//Interface can have a default definition of method.
//NEW FEATURE
default void method5() {
	System.out.println("Method5");
}

}

interface ExampleInterface2 { void method2(); }

// An interface can extend another interface // Class implementing SubInterface1 should // implement method3 and method1(from ExampleInterface1) interface SubInterface1 extends ExampleInterface1 { void method3(); }

/*

• //COMPILE ERROR IF UnCommented //Interface cannot extend a Class interface
• SubInterface2 extends InterfaceRules{ void method3(); } */

/* A Class can implement multiple interfaces / class SampleImpl implements ExampleInterface1, ExampleInterface2 { / * A class should implement all the methods in an interface. If either of * method1 or method2 is commented, it would result in compilation error. */ public void method2() { System.out.println("Sample Implementation for Method2"); }

public void method1() {
	System.out.println("Sample Implementation for Method1");
}

}

### /com/in28minutes/java/oops/interfaces/InterfaceExamples.java

package com.in28minutes.java.oops.interfaces;

public class InterfaceExamples { public static void main(String[] args) { Flyable flyable = new Bird(); flyable.fly(); } }

### /com/in28minutes/java/oops/interfaces/InterfaceTest.java

package com.in28minutes.java.oops.interfaces;

public class InterfaceTest { public static void main(String[] args) { Bird bird = new Bird(); bird.fly();// Bird is flying

	Aeroplane aeroplane = new Aeroplane();
	aeroplane.fly();// Aeroplane is flying

	// An interface reference variable can hold
	// objects of any implementation of interface
	Flyable flyable1 = new Bird();
	Flyable flyable2 = new Aeroplane();

}

}