M2E and having maven generated source folders as eclipse source folders
Solution 1:
You need to attach the source directory with the build-helper-plugin.
Like so:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<executions>
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/generated-sources/java/</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
You will also need to:
- Install the "Apt M2E Connector" from the Eclipse Marketplace. To do so click the error in the Overview tab of your pom.xml and select "Discover".
- Ensure there are no plugin execution filters for the build-helper-maven-plugin (see https://www.eclipse.org/m2e/documentation/m2e-execution-not-covered.html)
Solution 2:
Right-click the Error message:
Project configuration is not up-to-date with pom.xml Run project configuration update
in the Problems View and select Quick Fix and click Finish to select the default Update project configuration. This fixes it.