NetworkGraphImpl implements NetworkGraphService { @Override public synchronized void clear() { networkGraph = null; linkAdded.clear(); }  @Override synchronized void addLinks(List<Link> links); @Override synchronized void removeLinks(List<Link> links); @Override synchronized void clear(); @Override synchronized List<Link> getLinksInMst(); @Override synchronized List<Link> getAllLinks();  }
@Test public void testClear() throws Exception { networkGraphImpl.clear(); }