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Java 9 in JAVA_HOME
========================

    $ export JAVA_HOME=/path/to/jdk9
    $ mvn test

Using JDK Deprecated Modules
========================

Since Java 9 some modules previously bundled with the JDK are disabled by default.

Version 2.20.1 of the plugin added automatically "--add-modules java.se.ee" option to the command line of forked JVMs (unless already specified by user) in order to ease the transition of applications to Java 9.

From 2.21 onwards the plugin will not add that option: the recommended way of using those modules is to add explicit dependencies of the maintained versions of such libraries.

This is a reference of the versions which were bundled with Java 8:

**Commons Annotations**

javax.annotation:javax.annotation-api:1.3.1

**JavaBeans Activation Framework**

javax.activation:javax.activation-api:1.2.0

**Java Transaction API**

javax.transaction:javax.transaction-api:1.2

**JAXB**

javax.xml.bind:jaxb-api:2.3.0

org.glassfish.jaxb:jaxb-runtime:2.3.0 (implementation)

**JAX-WS**

javax.xml.ws:jaxws-api:2.3.0

com.sun.xml.ws:jaxws-rt:2.3.0 (implementation)

The source code for each of these is maintained at [https://github.com/javaee](https://github.com/javaee)



Java 9 in configuration of plugin
========================

The plugin provides you with configuration parameter `jvm` which can point to path of executable Java in JDK, e.g.:

    <configuration>
        <jvm>/path/to/jdk9/bin/java</jvm>
    </configuration>

Now you can run the build with tests on the top of Java 9.


Maven Toolchains with JDK 9
========================

This is an example on Windows to run unit tests with custom path to Toolchain **(-t ...)**.

    $ mvn -t D:\.m2\toolchains.xml test
    
Without **(-t ...)** the Toolchain should be located in **${user.home}/.m2/toolchains.xml**.

The content of **toolchains.xml** would become as follows however multiple different JDKs can be specified.

    <toolchains xmlns="http://maven.apache.org/POM/4.0.0"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
      <toolchain>
        <type>jdk</type>
        <provides>
          <version>9</version>
          <vendor>oracle</vendor>
          <id>jdk9</id>
        </provides>
        <configuration>
          <jdkHome>/path/to/jdk9</jdkHome>
        </configuration>
      </toolchain>
    </toolchains>

Your POM should specify the plugin which activates only particular JDK in *toolchains.xml* which specifies version **9**:

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-toolchains-plugin</artifactId>
        <version>1.1</version>
        <executions>
          <execution>
            <phase>validate</phase>
            <goals>
              <goal>toolchain</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <toolchains>
            <jdk>
              <version>9</version>
            </jdk>
          </toolchains>
        </configuration>
    </plugin>

Now you can run the build with tests on the top of Java 9.
