package com.iluwatar.callback;

/**
 * 
 * Implementation of task that need to be executed
 * 
 */
public class SimpleTask extends Task {

	@Override
	public void execute() {
		System.out.println("Perform some important activity.");
	}

}

package com.iluwatar.callback;

/**
 * 
 * Implementation of task that need to be executed
 * 
 */
public class SimpleTask extends Task {

	@Override
	public void execute() {
		System.out.println("Perform some important activity and after call the callback method.");
	}

}

Add unit test to show that the callback method is called.
Add unit test to show that the callback method is called.
