Maven and Java Extension

Question

I am trying to build and test a JavaFX application on a headless build server. Locally I am using TestFX and Monocle https://github.com/TestFX/Monocle and its working fine. However, I had to manually install Monocle into the java Extensions folder as per this question: JavaFX + maven + TestFX + monocle don't work together

Now I need to use a headless build server to automate our deployment. I can't figure out how to get this Java extension installed correctly with Maven, without doing it manually. This seemed to be the right feature: https://maven.apache.org/pom.html#Extensions,

<extensions>
    <extension>
        <groupId>org.testfx</groupId>
        <artifactId>openjfx-monocle</artifactId>
        <version>8u76-b04</version>
    </extension>
</extensions>  

but the tests fail with a NoClassDefFoundException (which doesn't happen if I manually build the jar into the Extensions). I don't know how to debug this, or if I'm even using the right feature. Any suggestions?

Answer 1

I had a similar headache some time ago. I solved it by copying both openjfx-monocle and all extensions from the extensions folder in a folder under /target and then set the extensions system property to that path. This way I could avoid the NoClassDefFoundException and also successfully run all test on Jenkins. Here is the profile part:

<!--
  This profile is used to make headless tests work with the Monocle Platform.
  It first copies the extensions from the JDK to the target/java-extensions folder.
  Then copies the openjfx-monocle implementation to the same folder.
  Afterwards it sets the extensions path to the folder with the copied extensions and the monocle platform.
-->
<profile>
  <id>headless-tests</id>
  <activation>
    <property>
      <name>headless.tests</name>
      <value>true</value>
    </property>
  </activation>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-resources-plugin</artifactId>
        <version>2.7</version>
        <executions>

          <execution>
            <id>copy-external-jars</id>
            <phase>generate-sources</phase>
            <goals>
              <goal>copy-resources</goal>
            </goals>
            <configuration>
              <outputDirectory>target/java-extensions</outputDirectory>
              <resources>
                <resource>
                  <directory>${java.home}/lib/ext/</directory>
                </resource>
              </resources>
            </configuration>

          </execution>

          <execution>
            <id>copy-monocle-to-extensions</id>
            <phase>generate-sources</phase>
            <goals>
              <goal>copy-resources</goal>
            </goals>
            <configuration>
              <outputDirectory>target/java-extensions</outputDirectory>
              <resources>
                <resource>
                  <directory>src/test/resources/test-lib</directory>
                  <includes>
                    <include>openjfx-monocle-8u76-b04.jar</include>
                  </includes>
                </resource>
              </resources>
            </configuration>
          </execution>

        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>2.18.1</version>
        <configuration>
          <argLine>-Djava.ext.dirs=${project.basedir}/target/java-extensions</argLine>
        </configuration>
      </plugin>
    </plugins>
  </build>
</profile>

In my case I copied the monocle jar from maven in the src/test/resources folder. This can further be improved by using Maven Dependency Plugin to copy the monocle jar directly with maven instead having it in src/test/resources.