Node extends GraphObject { @Override public int hashCode() { return Long.valueOf(id).hashCode(); } Node();  Node(long id); long getId(); void setId(long id); void addComponent(NodeComponent component); void addComponent(Class<? extends NodeComponent> key, NodeComponent component); C getComponent(Class<C> componentClass); boolean hasComponent(Class<? extends NodeComponent> key); Set<Class<? extends NodeComponent>> getAllComponentClasses(); @Override boolean equals(Object obj); @Override int hashCode();  }
@Test public void testHashCode() { assertEquals(new Long(0).hashCode(), n.hashCode()); }