### Question:
BaseEntityService extends BaseService implements IBaseEntityService<T> { @Override public T findEntity(Class<T> entityClass, Serializable id) throws EntityException { return getBaseEntityDao().findEntity(entityClass, id); } BaseEntityService(); @Override BaseEntityService<T> getSubClassEntityService(Class<T> entityClass); @Override void saveEntity(T entity); @Override void saveOrUpdateEntity(T entity); @Override void updateEntity(T entity); @Override void deleteEntity(T entity); @Override T findEntity(Class<T> entityClass, Serializable id); @Override T findEntity(Serializable id);  }### Answer:
@Test public void testFindEntityClassOfTSerializable() throws EntityException { for (String userId : userMap.keySet()) { TTestUser testUser = (TTestUser) baseEntityService.findEntity(TTestUser.class, userId); assertNotNull("findEntity方法加载对象，如果指定主键的id不存在，返回null！", testUser); } TTestUser testUser = (TTestUser) baseEntityService.findEntity(TTestUser.class, "1"); assertNull("findEntity方法加载对象，如果指定主键的id不存在，返回null！", testUser); }