How do I get Eclipse to resolve classes generated with Maven 2?

Question

I\'m using Google Protocol Buffers to generate some Java classes for my project. Using Maven 2 and its \"antrun\" plugin, these classes are freshly generated before compile,

Answer 1

m2eclipse supports this. First, add the path to your build path:

    org.codehaus.mojo
    build-helper-maven-plugin
    1.8
    
        
            add-source
            generate-sources
            
                add-source
            
            
                
                    ${project.build.directory}/generated-sources/java/
                
            
        
    

Second, add support for that to m2e:

    
        
            org.eclipse.m2e
            lifecycle-mapping
            1.0.0
            
                
                      
                        
                          
                            org.codehaus.mojo
                            build-helper-maven-plugin
                            [1.0,)
                            
                              parse-version
                              add-source
                              maven-version
                              add-resource
                              add-test-resource
                              add-test-source
                            
                          
                          
                            
                              true
                              true
                            
                          
                        
                    
                
            
        
    

The second step might not be necessary, if your eclipse installation has installed the "org.eclipse.m2e.discovery.lifecyclemapping.buildhelper.xml" plugin. This plugin is available via Window -> Preferences -> Maven -> Discovery. Currently, that does not work here at Eclipse Kepler, therefore, I fetched the JAR (linked from the xml shown in the Catalog URL) and extracted the fragments from org.eclipse.m2e.discovery.lifecyclemapping.buildhelper.xml by hand.