Add this to your plugins in your Maven build
<plugin>
<groupId>org.codehaus.gmavenplus</groupId>
<artifactId>gmavenplus-plugin</artifactId>
<version>1.6.2</version>
<executions>
<execution>
<goals>
<goal>addSources</goal>
<goal>addTestSources</goal>
<goal>generateStubs</goal>
<goal>compile</goal>
<goal>generateTestStubs</goal>
<goal>compileTests</goal>
<goal>removeStubs</goal>
<goal>removeTestStubs</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-all</artifactId>
<version>2.5.6</version>
<scope>runtime</scope>
<type>pom</type>
</dependency>
</dependencies>
</plugin>
You will also need to add Byte Buddy
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy</artifactId>
<version>1.9.12</version>
</dependency>