java.lang.IllegalArgumentException: id to load is required for loading

2009-10-24 10:58:57 org.zkoss.zk.ui.impl.UiEngineImpl handleError:1108

严重: >>java.lang.IllegalArgumentException: id to load is required for loading

>> at org.hibernate.event.LoadEvent.<init>(LoadEvent.java:51)

>> at org.hibernate.event.LoadEvent.<init>(LoadEvent.java:33)

>> at org.hibernate.impl.SessionImpl.get(SessionImpl.java:812)

>> at org.hibernate.impl.SessionImpl.get(SessionImpl.java:808)

>> at org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:182)

>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

>> at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

>> at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

>> at java.lang.reflect.Method.invoke(Method.java:585)

>> at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:357)

>>...

原因:使用JPA时，当使用find(Class<T> clazz, Serializable id);此方法時，若id為空，則會出現以上錯誤。