Sunday, May 5, 2013

Java EE main method - Hello World application

    Java SE has clearly defined entry point of the program execution - 'public static void main(String[] args)' method. However, when it comes to Java EE such an entry point is blurred. Can we create main method in Java EE?
The answer is: YES. The simplest possible solution is @Singleton bean with @Startup and @PostConstruct annotations:
import javax.annotation.PostConstruct;
import javax.ejb.Singleton;
import javax.ejb.Startup;

@Singleton
@Startup
public class MainMethodBean {
 
 @PostConstruct
 public void main() {
  System.out.println("Hello world from java EE!");
 }

}
We have just created our Java EE (EJB3.1) 'Hello world' application! Now you can configure your environment and deploy your EJB.

2 comments :

  1. You did't reduced complexity of issues discussed on your blog, did You? ;)

    ReplyDelete
    Replies
    1. It was off the top of my head :).

      Delete