# managed-executor-service: Managed Executor Service example

Rafael Benevides

> The `managed-executor-service` quickstart demonstrates how Java EE applications can submit tasks for asynchronous execution.

## What is it?

The Managed Executor Service (javax.enterprise.concurrent.ManagedExecutorService) allows Java EE applications to submit tasks for asynchronous execution. It is an extension of Java SE’s Executor Service (java.util.concurrent.ExecutorService) adapted to the Java EE platform requirements.

Managed Executor Service instances are managed by the application server, thus Java EE applications are forbidden to invoke any lifecycle related method.

A JAX-RS resource provides access to some operations that are executed asynchronously.

This quickstart does not contain any user interface. The tests must be run to verify everything is working correctly.

## Considerations for Use in a Production Environment

H2 Database

  This quickstart uses the H2 database included with WildFly Application Server 13. It is a lightweight, relational example datasource that is used for examples only. It is not robust or scalable, is not supported, and should NOT be used in a production environment.

Datasource Configuration File

  This quickstart uses a `*-ds.xml` datasource configuration file for convenience and ease of database configuration. These files are deprecated in WildFly and should not be used in a production environment. Instead, you should configure the datasource using the Management CLI or Management Console. Datasource configuration is documented in the Configuration Guide.

## System Requirements

The application this project produces is designed to be run on WildFly Application Server 13 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 WILDFLY_HOME

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

## Start the WildFly Standalone Server

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

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

       $ WILDFLY_HOME/bin/standalone.sh

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

## Run the Arquillian Tests

This quickstart provides Arquillian tests. By default, these tests are configured to be skipped since Arquillian tests require the use of a container.

Note | The Arquillian tests deploy the application, so make sure you undeploy the quickstart before you begin.

Follow these steps to run the tests.

1. Start the WildFly server as described above.

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

3. Type the following command to run the `verify` goal with the `arq-remote` profile activated.

       $ mvn clean verify -Parq-remote

Note | You can also let Arquillian manage the WildFly server by using the `arq-managed` profile, meaning the tests will start the server for you. This profile requires that you provide Arquillian with the location of the WildFly server, either by setting the `JBOSS_HOME` environment variable, or by setting the `jbossHome` property in the `arquillian.xml` file. For more information, see Run the Arquillian Tests.

## Investigate the Console Output

When you run the Arquillian tests, Maven prints summary of the performed tests to the console. You should see the following results.

    -------------------------------------------------------
     T E S T S
    -------------------------------------------------------
    Running org.jboss.as.quickstarts.managedexecutorservice.test.ProductsRestClientIT
    org.xnio.Xnio <clinit>
    INFO: XNIO version 3.3.4.Final
    org.xnio.nio.NioXnio <clinit>
    INFO: XNIO NIO Implementation Version 3.3.4.Final
    org.jboss.remoting3.EndpointImpl <clinit>
    INFO: JBoss Remoting version 4.0.18.Final
    org.jboss.as.quickstarts.managedexecutorservice.test.ProductsRestClientIT testRestResources
    INFO: creating a new product
    org.jboss.as.quickstarts.managedexecutorservice.test.ProductsRestClientIT testRestResources
    INFO: Product created. Executing a long running task
    org.jboss.as.quickstarts.managedexecutorservice.test.ProductsRestClientIT testRestResources
    INFO: Deleting all products
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 5.619 sec - in org.jboss.as.quickstarts.managedexecutorservice.test.ProductsRestClientIT

    Results :

    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

## Investigate the Server Console Output

Look at the WildFly console or Server log and you should see log messages like the following:

    INFO  [ProductResourceRESTService] (default task-51) Will create a new Product on other Thread
    INFO  [ProductResourceRESTService] (default task-51) Returning response
    INFO  [PersitTask] (EE-ManagedExecutorService-default-Thread-5) Begin transaction
    INFO  [PersitTask] (EE-ManagedExecutorService-default-Thread-5) Persisting a new product
    INFO  [PersitTask] (EE-ManagedExecutorService-default-Thread-5) Commit transaction
    INFO  [ProductResourceRESTService] (default task-52) Submitting a new long running task to be executed
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [LongRunningTask] (EE-ManagedExecutorService-default-Thread-5) Starting a long running task
    INFO  [LongRunningTask] (EE-ManagedExecutorService-default-Thread-5) Analysing A Product
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Waiting for the result to be available...
    INFO  [ProductResourceRESTService] (default task-52) Result is available. Returning result...56
    INFO  [ProductResourceRESTService] (default task-53) Will delete all Products on other Thread
    INFO  [ProductResourceRESTService] (default task-53) Returning response
    INFO  [DeleteTask] (EE-ManagedExecutorService-default-Thread-5) Begin transaction
    INFO  [DeleteTask] (EE-ManagedExecutorService-default-Thread-5) Deleting all products
    INFO  [DeleteTask] (EE-ManagedExecutorService-default-Thread-5) Commit transaction. Products deleted: 1

Note that the PersistTask and DeleteTask were executed after ProductResourceRESTService sends a Response. The only exception is for LongRunningTask where ProductResourceRESTService waits for its response.

## Server Log: Expected Warnings and Errors

You will see the following warnings in the server log. You can ignore these warnings.

    WFLYJCA0091: -ds.xml file deployments are deprecated. Support may be removed in a future version.

    HHH000431: Unable to determine H2 database version, certain features may not work

## 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 WildFly server, and build and deploy a quickstart, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts.

To run the tests in Red Hat JBoss Developer Studio, you must first set the active Maven profile in project properties to one of the following:

- `arq-remote`: This setting is used for a remote server. JBoss Developer Studio starts the server for you.

- `arq-managed`: This setting is used for a managed server. If you use this setting, you must start the server before you run the tests.

Then, to run the tests, right click on the project or individual classes and select Run As –> JUnit Test in the context menu.

## 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