code: protected ServiceTracker<IExecutors, ?> getExecutorsServiceTracker(BundleContext bundleContext) throws InvalidSyntaxException {
  		ServiceTracker<IExecutors, ?> tracker = new ServiceTracker<IExecutors, Object>(
  				bundleContext,
  				bundleContext.createFilter(
  						"(&(" + Constants.OBJECTCLASS + "=" + IExecutors.class.getName() +  //$NON-NLS-1$ //$NON-NLS-2$
  						")(name=" + getServletBundleName() + "))"), //$NON-NLS-1$ //$NON-NLS-2$
  						null);
  		tracker.open();
  		return tracker;
  	}
docs: Returns an opened ServiceTracker for the Aggregator exectors provider.
  The executors provider is are created by the bundle activator and is
  shared by all Aggregator instances created from the same bundle.
  
  @param bundleContext
  The contributing bundle context
  @return The opened service tracker
  @throws InvalidSyntaxException