### Question:
LineageGraphMap { public static Map<Object, Future<Graph>> getInstance() { return lineageGraphMap; }  static Map<Object, Future<Graph>> getInstance(); static final Map<Object, Future<Graph>> lineageGraphMap; }### Answer:
@Test public void testGetInstance() throws Exception { Map<Object, Future<Graph>> map1 = LineageGraphMap.getInstance(); Map<Object, Future<Graph>> map2 = LineageGraphMap.getInstance(); assertNotNull( map1 ); assertEquals( map1, map2 ); }