Bug 68011 [java search] "Search the JRE System Libraries" looks like a local preference but behaves as a global one... [search]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/search/JavaSearchQuery.java
fSearchResult.addMatch(match);
			} else {
				fSearchResult.addMatch(match, participant);
			}
		}
		
		protected SearchRequestor(IQueryParticipant participant, JavaSearchResult result) {
			super();
			fParticipant= participant;
			fSearchResult= result;
		}
	}
	
	public IStatus run(IProgressMonitor monitor) {
		final JavaSearchResult textResult= (JavaSearchResult) getSearchResult();
		textResult.removeAll();
		
		SearchEngine engine= new SearchEngine();
		try {
			int totalTicks= 1000;
			IProject[] projects= JavaSearchScopeFactory.getInstance().getProjects(fPatternData.getScope());
			final SearchParticipantRecord[] participantDescriptors= SearchParticipantsExtensionPoint.getInstance().getSearchParticipants(projects);
			final int[] ticks= new int[participantDescriptors.length];
			for (int i= 0; i < participantDescriptors.length; i++) {
				final int iPrime= i;
				ISafeRunnable runnable= new ISafeRunnable() {
					public void handleException(Throwable exception) {
						ticks[iPrime]= 0;
						String message= SearchMessages.JavaSearchQuery_error_participant_estimate; 
						JavaPlugin.log(new Status(IStatus.ERROR, JavaPlugin.getPluginId(), 0, message, exception));