The submodules are not cleaned.

Author: HansMartinA

tests/org.emftext.language.java.test/pom.xml

@@ -25,6 +25,26 @@
                     </archive>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-clean-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>default-clean</id>
+                        <configuration>
+                            <excludeDefaultDirectories>true</excludeDefaultDirectories>
+                            <filesets>
+                                <fileset>
+                                    <directory>${project.build.directory}</directory>
+                                    <excludes>
+                                        <exclude>src-bulk/**/*</exclude>
+                                    </excludes>
+                                </fileset>
+                            </filesets>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>