Spring Event Handling/Message exchanging

The below example gives an overview of how the events in Spring is handled using annotations and declarative approach. 
In Spring, we can handle both custom events and Spring Events.

For custom events, we need to write both publisher, listener and event classes and pass the event to publisher.publish(ApplicationEvent event) method. Whereas, Spring events (eg.Context events) are published by Spring. We need to write listeners to handle those.

Publisher and Event classes

 package com.javarephrased.standalone.eg.eventhandling;  
 import org.springframework.beans.factory.annotation.Autowired;  
 import org.springframework.context.ApplicationEvent;  
 import org.springframework.context.ApplicationEventPublisher;  
 import org.springframework.context.ApplicationEventPublisherAware;  
 import org.springframework.stereotype.Component;  
 @Component  
 public class Publisher implements ApplicationEventPublisherAware{  
      @Autowired  
      ApplicationEventPublisher publisher;  
      public void setApplicationEventPublisher(ApplicationEventPublisher arg0) {  
           this.publisher = publisher;  
      }  
      public void publish(){  
           publisher.publishEvent(new MyEvent(this, "type1", "Event Object"));  
      }  
 }  
 class MyEvent extends ApplicationEvent{  
      String eventType;  
      String eventObject;  
      public MyEvent(Object source, String eventType, String eventObject) {  
           super(source);  
           this.eventType = eventType;  
           this.eventObject = eventObject;  
      }  
      public String getEventType() {  
           return eventType;  
      }  
      public String getEventObject() {  
           return eventObject;  
      }  
 }  

Listener class

 
 package com.javarephrased.standalone.eg.eventhandling;
 import org.springframework.context.ApplicationListener;  
 import org.springframework.context.event.ContextClosedEvent;  
 import org.springframework.context.event.ContextRefreshedEvent;  
 import org.springframework.context.event.ContextStartedEvent;  
 import org.springframework.context.event.EventListener;  
 import org.springframework.stereotype.Component;  
 /**  
  * Custom Event Publisher published the My Event   
  * Custom Event Listener Registered for My Event to get notifications  
  * @author Naresh Doniparti       
  */  
 @Component  
 public class CustomEventListener{  
      @EventListener  
      public String onApplicationEvent(MyEvent ev) {  
           System.out.println("CustomEventListener MyEvent Details :"+ev.getEventObject()+", "+ev.getEventType());  
           System.out.println("I will do some action for the Myevent");  
           return "SUCESS";  
      }  
 }  
 /**  
  * This class registers ContextRefreshedEvent published by ApplicationContext  
  * @author naresh  
  *  
  */  
 @Component  
 class ContextRefreshedListener implements ApplicationListener<ContextRefreshedEvent>{  
      public void onApplicationEvent(ContextRefreshedEvent event) {  
           System.out.println("ContextRefreshedListener Time: "+event.getTimestamp());            
      }  
 }  

Logs

 ContextRefreshedListener Time: 1443945056727  
 CustomEventListener MyEvent Details :Event Object, type1  
 I will do some action for the Myevent