516612: IllegalArgumentException below MissingNatureDetector.<init> (…

…thrown in InternalJobGroup.<init>)

Move JobGroup initialization into early startup to avoid nested bundle
activation from class loading. 

Bug: 516612
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=516612

org.eclipse.epp.mpc.ui/src/org/eclipse/epp/internal/mpc/ui/discovery/MissingNatureDetector.java

@@ -38,7 +38,7 @@ public class MissingNatureDetector implements IStartup, IPropertyChangeListener
 
 	public static final String ENABLEMENT_PROPERTY = "org.eclipse.epp.mpc.naturelookup"; //$NON-NLS-1$
 
-	private final JobGroup allJobs = new JobGroup(Messages.MissingNatureDetector_Title, 3, 0);
+	private JobGroup allJobs;
 
 	private final Set<String> detectedNatures = new HashSet<String>();
 
@@ -66,6 +66,10 @@ public void resourceChanged(IResourceChangeEvent event) {
 		}
 	};
 
+	public MissingNatureDetector() {
+		super();
+	}
+
 	private void triggerNatureLookup(final String natureId) {
 		synchronized (lookupJobs) {
 			if (detectedNatures.contains(natureId)) {
@@ -111,13 +115,13 @@ private void showProposalsIfReady() {
 	}
 
 	public void earlyStartup() {
+		allJobs = new JobGroup(Messages.MissingNatureDetector_Title, 3, 0);
 		IPreferenceStore preferenceStore = MarketplaceClientUiPlugin.getInstance().getPreferenceStore();
 		preferenceStore.addPropertyChangeListener(this);
 		boolean preferenceValue = preferenceStore.getBoolean(ENABLEMENT_PROPERTY);
 		if (preferenceValue) {
 			ResourcesPlugin.getWorkspace().addResourceChangeListener(projectOpenListener);
 		}
-
 	}
 
 	public void propertyChange(PropertyChangeEvent event) {