Why is getState() returning null?

Hi Community,

I tried to persist some configuration values. I followed the instructions of the documentation http://confluence.jetbrains.com/display/IDEADEV/Persisting+State+of+Components
I created a Service like this:

@State(name = "ConfigurationServiceImpl",
       storages = {
               @Storage(id = "main", file = StoragePathMacros.APP_CONFIG + "tdaconfig.xml")
       }
)
public class ConfigurationServiceImpl implements ConfigurationService, PersistentStateComponent<ConfigurationServiceImpl.State> {
    class State {
        public Set<String> excludedClassNames = new HashSet<String>();
    }

    public State configurationState;

    @Override
    public void addExcludedClassName(String excludedClassName) {
        getState().excludedClassNames.add(excludedClassName);
    }

    @Override
    public void clearExcludedClassNames() {
        getState().excludedClassNames.clear();
    }

    @Override
    public boolean isClassExcluded(TDAClass tdaClass) {
        for (String excludedClassName : getState().excludedClassNames) {
            if (tdaClass.getName().equals(excludedClassName)) {
                return true;
            }
        }
        return false;
    }

    @Override
    public Set<String> getExcludedClassNames() {
        return getState().excludedClassNames;
    }

    @Nullable
    @Override
    public State getState() {
        return configurationState;
    }


    @Override
    public void loadState(ConfigurationServiceImpl.State state) {
        configurationState = state;
    }
}

The problem that I have is if I try to use the getExcludedClassNames() Method I get a NullPointerException. I tried to use the ConfigurationService with the stored data in my ExcludedClasses configurable.

<applicationService serviceInterface="analyzer.service.ConfigurationService"
                    serviceImplementation="analyzer.service.impl.ConfigurationServiceImpl">
</applicationService>
<applicationConfigurable instance="analyzer.configuration.ExcludedClasses"/>

I don't see what I'm doing wrong.
I Think the loadState Method is never called, but I don't know why.

Markus