grandchild3.parent = child1;
child1.children = Lists.newArrayList(grandchild3);
ObjectStoreSession sess1 = store.beginSession();
sess1.store(root).now();
Key key = sess1.getKey(child2);
ObjectStoreSession sess2 = store.beginSession();
Node child2a = sess2.load(key).activate("**.children", "**.parent", "!**.parent.children").now();