Enterprise Scala Beans or Scala on a JEE application server

Once i was thinking about writing Enterprise Java Beans(EJBs) with the Scala programming language. This should be easy as Scala greatly incorporates with existing Java code bases. But let’s create a small test to verify this!

For this example, i am using Apache TomEE 1.5.1 as a JEE Web Profile certified server and Scala 2.10 to create a small stateless session bean and invoke it from a servlet. The stateless bean is injected to the servlet using CDI. I use IntelliJ 12 as my favorite IDE.

Here is the Scala code for the stateless session bean:

package de.mirkosertic.scala

import javax.ejb.Stateless
import util.Random

@Stateless
class StatelessBean {

   val random = Random

   def sayHello() = "Hello " + random.nextInt
}

I use the JEE @Stateless annotation to mark the Scala class as a stateless session bean. The bean has a public sayHello() method, which just returns the string “Hello ” concatenated with a random number. Here is the JEE servlet which uses the JEE bean:

package de.mirkosertic.java;

import de.mirkosertic.scala.StatelessBean;

import javax.ejb.EJB;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet("/servlet")
public class TestServlet extends HttpServlet {

    @EJB
    StatelessBean statelessBean;

    @Override
    protected void doGet(HttpServletRequest aRequest, HttpServletResponse aResponse) throws ServletException, IOException {
        PrintWriter theWriter = aResponse.getWriter();
        theWriter.print("<html><body>");
        theWriter.print(statelessBean.sayHello());
        theWriter.print("</body></html>");
    }
}

After compiling it and invoking it from the browser, we see a “Hello” text with a random number. It is working! We can create Enterprise Java Beans with Scala, so we have Enterprise Scala Beans :-)

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