24) Interfaces

Need of Interfaces:

Example:

Suppose we have two classes Programmer and Manager both of them extend some common feature from Employee class.Now let say we have the below requirement/behavior to implement

That's the reason why interface are needed

Code:

package com.gs.ilp.corejava.interfaces;

public interface Interviewer {
	public void conductInterview();
}

package com.gs.ilp.corejava.interfaces;

public interface Trainable {
	public void attendTraining();
}

package com.gs.ilp.corejava.interfaces;

public class Employeeee {
	String name;
	String address;
	String phoneNumber;
	String experience;
}

package com.gs.ilp.corejava.interfaces;

public class Manager extends Employeeee implements Interviewer, Trainable {
	int teamSize;
	void reportProjectStatus() {
	}
	public void attendTraining() {
		System.out.println("Mgr - attendTraining");
	}
	public void conductInterview() {
		System.out.println("Mgr - conductInterview");
	}
}

package com.gs.ilp.corejava.interfaces;

public class Programmer extends Employeeee implements Trainable {
	String[] programmingLanguages;
	void writeCode() {
	}
	public void attendTraining() {
		System.out.println("Prog - attendTraining");
	}
}

package com.gs.ilp.corejava.interfaces;

public class TestInterfaces {
	public static void main(String[] args) {
		Manager manager = new Manager();
		manager.attendTraining();
		manager.conductInterview();

		Programmer programmer = new Programmer();
		programmer.attendTraining();
	}
}