Hibernate flushing: Cannot release connection

org.springframework.jdbc.UncategorizedSQLException: Hibernate flushing: Cannot release connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Already closed.; nested exception is java.sql.SQLException: Already closed.

Caused by: java.sql.SQLException: Already closed.

这是什么异常，原因是什么呢

http://blog.csdn.net/gavinloo/article/details/12206763 看一下