Chapter 2. Using Maven with JBoss EAP

Apache Maven is a distributed build automation tool used in Java application development to create, manage, and build software projects. Maven uses standard configuration files called Project Object Model, or POM, files to define projects and manage the build process. POMs describe the module and component dependencies, build order, and targets for the resulting project packaging and output using an XML file. This ensures that the project is built in a correct and uniform manner.

Maven achieves this by using a repository. A Maven repository stores Java libraries, plug-ins, and other build artifacts. The default public repository is the Maven 2 Central Repository, but repositories can be private and internal within a company with a goal to share common artifacts among development teams. Repositories are also available from third-parties. JBoss EAP includes a Maven repository that contains many of the requirements that Java EE developers typically use to build applications on JBoss EAP. To configure your project to use this repository, see Configure the JBoss EAP Maven Repository.

For more information about Maven, see Welcome to Apache Maven.

For more information about Maven repositories, see Apache Maven Project - Introduction to Repositories.

The Project Object Model, or POM, file is a configuration file used by Maven to build projects. It is an XML file that contains information about the project and how to build it, including the location of the source, test, and target directories, the project dependencies, plug-in repositories, and goals it can execute. It can also include additional details about the project including the version, description, developers, mailing list, license, and more. A pom.xml file requires some configuration options and will default all others.

The schema for the pom.xml file can be found at http://maven.apache.org/maven-v4_0_0.xsd.

For more information about POM files, see the Apache Maven Project POM Reference.

Minimum Requirements of a Maven POM File

The minimum requirements of a pom.xml file are as follows:

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.jboss.app</groupId>
  <artifactId>my-app</artifactId>
  <version>1</version>
</project>

The Maven settings.xml file contains user-specific configuration information for Maven. It contains information that must not be distributed with the pom.xml file, such as developer identity, proxy information, local repository location, and other settings specific to a user.

There are two locations where the settings.xml can be found:

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <profiles>
    <!-- Configure the JBoss EAP Maven repository -->
    <profile>
      <id>jboss-eap-maven-repository</id>
      <repositories>
        <repository>
          <id>jboss-eap</id>
          <url>file:///path/to/repo/jboss-eap-7.1.0.GA-maven-repository/maven-repository</url>
          <releases>
            <enabled>true</enabled>
          </releases>
          <snapshots>
            <enabled>false</enabled>
          </snapshots>
        </repository>
      </repositories>
      <pluginRepositories>
        <pluginRepository>
          <id>jboss-eap-maven-plugin-repository</id>
          <url>file:///path/to/repo/jboss-eap-7.1.0.GA-maven-repository/maven-repository</url>
          <releases>
            <enabled>true</enabled>
          </releases>
          <snapshots>
            <enabled>false</enabled>
          </snapshots>
        </pluginRepository>
      </pluginRepositories>
    </profile>
  </profiles>
  <activeProfiles>
    <!-- Optionally, make the repository active by default -->
    <activeProfile>jboss-eap-maven-repository</activeProfile>
  </activeProfiles>
</settings>

The schema for the settings.xml file can be found at http://maven.apache.org/xsd/settings-1.0.0.xsd.

A repository manager is a tool that allows you to easily manage Maven repositories. Repository managers are useful in multiple ways:

For more information about Maven repository managers, see Best Practice - Using a Repository Manager.

Commonly used Maven repository managers

If you plan to use Maven command line to build and deploy your applications to JBoss EAP, you must download and install Maven. If you plan to use Red Hat JBoss Developer Studio to build and deploy your applications, you can skip this procedure as Maven is distributed with Red Hat JBoss Developer Studio.

There are two ways to download the JBoss EAP Maven repository:

There are three ways to install the JBoss EAP Maven repository.

Configure the JBoss EAP Maven Repository Using the Maven Settings

This is the recommended approach. Maven settings used with a repository manager or repository on a shared server provide better control and manageability of projects. Settings also provide the ability to use an alternative mirror to redirect all lookup requests for a specific repository to your repository manager without changing the project files. For more information about mirrors, see http://maven.apache.org/guides/mini/guide-mirror-settings.html.

This method of configuration applies across all Maven projects, as long as the project POM file does not contain repository configuration.

This section describes how to configure the Maven settings. You can configure the Maven install global settings or the user’s install settings.

Configure the JBoss EAP Maven Repository Using the Project POM

You must plan carefully if you decide to configure repositories using project POM file. Transitively included POMs are an issue with this type of configuration since Maven has to query the external repositories for missing artifacts and this slows the build process. It can also cause you to lose control over where your artifacts are coming from.

Determine the URL of the JBoss EAP Repository

The repository URL depends on where the repository is located. You can configure Maven to use any of the following repository locations.

The artifacts and dependencies needed to build and deploy applications to Red Hat JBoss Enterprise Application Platform are hosted on a public repository. You must direct Maven to use this repository when you build your applications. This section covers the steps to configure Maven if you plan to build and deploy applications using Red Hat JBoss Developer Studio.

Maven is distributed with Red Hat JBoss Developer Studio, so it is not necessary to install it separately. However, you must configure Maven for use by the Java EE Web Project wizard for deployments to JBoss EAP. The procedure below demonstrates how to configure Maven for use with JBoss EAP by editing the Maven configuration file from within Red Hat JBoss Developer Studio.

The JBoss EAP Maven repository is now configured for use with Red Hat JBoss Developer Studio.

This section describes the usage of Bill of Materials (BOM) POMs for Red Hat JBoss Enterprise Application Platform.

A BOM is a Maven pom.xml (POM) file that specifies the versions of all runtime dependencies for a given module. Version dependencies are listed in the dependency management section of the file.

A project uses a BOM by adding its groupId:artifactId:version (GAV) to the dependency management section of the project pom.xml file and specifying the <scope>import</scope> and <type>pom</type> element values.

Supported Maven Artifacts

As part of the product build process, all runtime components of JBoss EAP are built from source in a controlled environment. This helps to ensure that the binary artifacts do not contain any malicious code, and that they can be supported for the life of the product. These artifacts can be easily identified by the -redhat version qualifier, for example 1.0.0-redhat-1.

Adding a supported artifact to the build configuration pom.xml file ensures that the build is using the correct binary artifact for local building and testing. Note that an artifact with a -redhat version is not necessarily part of the supported public API, and might change in future revisions. For information about the public supported API, see the Javadoc documentation included in the release.

For example, to use the supported version of Hibernate, add something similar to the following to your build configuration.

<dependency>
  <groupId>org.hibernate</groupId>
  <artifactId>hibernate-core</artifactId>
  <version>5.1.6.Final-redhat-1</version>
  <scope>provided</scope>
</dependency>

Notice that the above example includes a value for the <version/> field. However, it is recommended to use Maven dependency management for configuring dependency versions.

Dependency Management

Maven includes a mechanism for managing the versions of direct and transitive dependencies throughout the build. For general information about using dependency management, see the Apache Maven Project: Introduction to the Dependency Mechanism.

Using one or more supported Red Hat dependencies directly in your build does not guarantee that all transitive dependencies of the build will be fully supported Red Hat artifacts. It is common for Maven builds to use a mix of artifact sources from the Maven central repository and other Maven repositories.

There is a dependency management BOM included in the JBoss EAP Maven repository, which specifies all the supported JBoss EAP binary artifacts. This BOM can be used in a build to ensure that Maven will prioritize supported JBoss EAP dependencies for all direct and transitive dependencies in the build. In other words, transitive dependencies will be managed to the correct supported dependency version where applicable. The version of this BOM matches the version of the JBoss EAP release.

<dependencyManagement>
  <dependencies>
    ...
    <dependency>
      <groupId>org.jboss.bom</groupId>
      <artifactId>eap-runtime-artifacts</artifactId>
      <version>7.1.0.GA</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
    ...
  </dependencies>
</dependencyManagement>

JBoss EAP Java EE Specs BOM

The jboss-eap-javaee7 BOM contains the Java EE Specification API JARs used by JBoss EAP.

To use this BOM in a project, add a dependency for the GAV that contains the version of the JSP and Servlet API JARs needed to build and deploy the application.

The following example uses the 1.1.0.Final-redhat-1 version of the jboss-eap-javaee7 BOM.

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.jboss.spec</groupId>
      <artifactId>jboss-javaee-7.0</artifactId>
      <version>1.1.0.Final-redhat-1</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
    ...
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>org.jboss.spec.javax.servlet</groupId>
    <artifactId>jboss-servlet-api_3.1_spec</artifactId>
    <scope>provided</scope>
  </dependency>
  <dependency>
    <groupId>org.jboss.spec.javax.servlet.jsp</groupId>
    <artifactId>jboss-jsp-api_2.3_spec</artifactId>
    <scope>provided</scope>
  </dependency>
  ...
</dependencies>

JBoss EAP BOMs Available for Application Development

The following table lists the Maven BOMs that are available for application development.

The following example uses the 7.1.0.GA version of the jboss-eap-javaee7 BOM.

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.jboss.bom</groupId>
      <artifactId>jboss-eap-javaee7</artifactId>
      <version>7.1.0.GA</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
    ...
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <scope>provided</scope>
  </dependency>
  ...
</dependencies>

JBoss EAP Client BOMs

The client BOMs do not create a dependency management section or define dependencies. Instead, they are an aggregate of other BOMs and are used to package the set of dependencies necessary for a remote client use case.

The wildfly-ejb-client-bom and wildfly-jms-client-bom BOMs are managed by the jboss-eap-javaee7 BOM, so there is no need to manage the versions in your project dependencies.

The following is an example of how to add the wildfly-ejb-client-bom and wildfly-jms-client-bom client BOM dependencies to your project.

<dependencyManagement>
  <dependencies>
    <!-- jboss-eap-javaee7: JBoss stack of the Java EE APIs and related components.  -->
    <dependency>
      <groupId>org.jboss.bom</groupId>
      <artifactId>jboss-eap-javaee7</artifactId>
      <version>7.1.0.GA</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
  ...
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>org.jboss.eap</groupId>
    <artifactId>wildfly-ejb-client-bom</artifactId>
    <type>pom</type>
  </dependency>
  <dependency>
    <groupId>org.jboss.eap</groupId>
    <artifactId>wildfly-jms-client-bom</artifactId>
    <type>pom</type>
  </dependency>
  ...
</dependencies>

For more information about Maven Dependencies and BOM POM files, see Apache Maven Project - Introduction to the Dependency Mechanism.