06 Feb 2013 , tagged: OSGI, Maven, SCR

Type Incompatibility With Maven SCR Plugin

Yesterday I ran into a most strange error when compiling one of my OSGI bundles:

[ERROR] Failed to execute goal org.apache.felix:maven-scr-plugin:1.7.4:scr (generate-scr-scrdescriptor) on project XXX: A type incompatibility occured while executing org.apache.felix:maven-scr-plugin:1.7.4:scr: com.thoughtworks.qdox.model.Annotation cannot be cast to java.util.List

I saw several variations of that error and was initially clueless as how to fix it. However, I eventually found the problem:

@Service(value = { MyService.class, ManagedService.class })
@Component(immediate = true)
@Properties(@Property(name = "foo", value = "bar"))
public class NissanAutoDataUrlGenerator implements ManagedService { }

The mistake is that the @Properties annotation takes an array as it’s parameter. Eclipse does not mark the above as an error, however, the Maven plugin is not happy about it. Here’s the correct code:

@Service(value = { MyService.class, ManagedService.class })
@Component(immediate = true)
@Properties({ @Property(name = "foo", value = "bar") } )
public class NissanAutoDataUrlGenerator implements ManagedService { }