# helloworld-singleton: Helloworld Using a Singleton EJB

Serge Pagop

> The `helloworld-singleton` quickstart demonstrates an EJB Singleton Bean that is instantiated once and maintains state for the life of the session.

## What is it?

The `helloworld-singleton` quickstart demonstrates the use of an EJB Singleton Bean in JBoss Enterprise Application Platform Server. It is instantiated once and maintains its state for the life of the session.

## System Requirements

The application this project produces is designed to be run on JBoss Enterprise Application Platform Server 7.2 or later.

All you need to build this project is Java 8.0 (Java SDK 1.8) or later and Maven 3.3.1 or later. See Configure Maven to Build and Deploy the Quickstarts to make sure you are configured correctly for testing the quickstarts.

## Use of EAP_HOME

In the following instructions, replace `EAP_HOME` with the actual path to your JBoss EAP installation. The installation path is described in detail here: Use of EAP_HOME and JBOSS_HOME Variables.

## Start the JBoss EAP Standalone Server

1. Open a terminal and navigate to the root of the JBoss EAP directory.

2. Start the JBoss EAP server with the default profile by typing the following command.

       $ EAP_HOME/bin/standalone.sh

   Note | For Windows, use the `EAP_HOME\bin\standalone.bat` script.

## Build and Deploy the Quickstart

1. Make sure you start the JBoss EAP server as described above.

2. Open a terminal and navigate to the root directory of this quickstart.

3. Type the following command to build the artifacts.

       $ mvn clean package wildfly:deploy

This deploys the `helloworld-singleton/target/helloworld-singleton.war` to the running instance of the server.

You should see a message in the server log indicating that the archive deployed successfully.

## Access the Application

The application will be running at the following URL: http://localhost:8080/helloworld-singleton/.

This example demonstrates a singleton session bean that maintains state information for 2 variables: `Increment A` and `Increment B`.

A counter is incremented when you click on the link to the variable name. If you close and restart your browser, or if you have multiple browsers, you can see that the counter always increments the last value. These values are maintained until you restart the server.

To test the singleton bean, click on either Increment A or Increment B. The result page will give you the current value of the variable.

## Undeploy the Quickstart

When you are finished testing the quickstart, follow these steps to undeploy the archive.

1. Make sure you start the JBoss EAP server as described above.

2. Open a terminal and navigate to the root directory of this quickstart.

3. Type this command to undeploy the archive:

       $ mvn wildfly:undeploy

## Run the Quickstart in Red Hat JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts or run the Arquillian tests in Red Hat JBoss Developer Studio or from Eclipse using JBoss tools. For general information about how to import a quickstart, add a JBoss EAP server, and build and deploy a quickstart, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts.

## Debug the Application

If you want to debug the source code of any library in the project, run the following command to pull the source into your local repository. The IDE should then detect it.

    $ mvn dependency:sources