Bug 139483 IDEIdleHelper should be a system job
RC2 The IDEIdleHelper is not a system job so you periodically get a "Collecting garbage" job showing up in the ProgressView.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/IDEIdleHelper.java
private long lastGC = System.currentTimeMillis();
	/**
	 * The maximum gc duration. If this value is exceeded, the
	 * entire explicit gc mechanism is disabled.
	 */
	private int maxGC = DEFAULT_GC_MAX;
	/**
	 * The minimum time interval until the next garbage collection
	 */
	private int minGCInterval = DEFAULT_GC_INTERVAL;
	/**
	 * The time interval until the next garbage collection
	 */
	private int nextGCInterval = DEFAULT_GC_INTERVAL;
	
	private Job gcJob = new Job(IDEWorkbenchMessages.IDEIdleHelper_backgroundGC) {
		protected IStatus run(IProgressMonitor monitor) {
			final Display display = configurer.getWorkbench().getDisplay();
			if (display != null && !display.isDisposed()) {
				final long start = System.currentTimeMillis();
				System.gc();
				System.runFinalization();
				lastGC = start;
				final int duration = (int) (System.currentTimeMillis() - start);
				if (Policy.DEBUG_GC) {
					System.out.println("Explicit GC took: " + duration); 
				}
				if (duration > maxGC) {
					if (Policy.DEBUG_GC) {
						System.out.println("Further explicit GCs disabled due to long GC");