我正在使用Java，hibernate，sqlserver 2008 R2，Jboss，
获得此例外，
WARNING [com.microsoft.sqlserver.jdbc.internals.TDS.Reader] (pool-26-thread-7) ConnectionID:4 TDS header contained invalid packet length:12590; packet size:8000
2013-05-21 15:59:15,777 SEVERE [com.microsoft.sqlserver.jdbc.internals.TDS.Reader] (pool-26-thread-7) ConnectionID:4 got unexpected value in TDS response at offset:7992
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) Exception in thread "pool-25-thread-2"
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) org.hibernate.TransactionException: JDBC rollback failed
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at org.hibernate.transaction.JDBCTransaction.rollback(JDBCTransaction.java:204)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.wideplay.warp.persist.hibernate.HibernateLocalTxnInterceptor.rollbackIfNecessary(HibernateLocalTxnInterceptor.java:149)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.wideplay.warp.persist.hibernate.HibernateLocalTxnInterceptor.invoke(HibernateLocalTxnInterceptor.java:72)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.softpak.marserm.engine.library.impl.JobReportStatusUtil.updateReportStatus(Unknown Source)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.softpak.marserm.engine.library.impl.ExecutableJob.run(Unknown Source)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at java.lang.Thread.run(Thread.java:662)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed.
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:170)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.microsoft.sqlserver.jdbc.SQLServerConnection.checkClosed(SQLServerConnection.java:304)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at com.microsoft.sqlserver.jdbc.SQLServerConnection.rollback(SQLServerConnection.java:1655)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at org.jboss.resource.adapter.jdbc.BaseWrapperManagedConnection.jdbcRollback(BaseWrapperManagedConnection.java:697)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at org.jboss.resource.adapter.jdbc.WrappedConnection.rollback(WrappedConnection.java:500)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at org.hibernate.transaction.JDBCTransaction.rollbackAndResetAutoCommit(JDBCTransaction.java:217)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) at org.hibernate.transaction.JDBCTransaction.rollback(JDBCTransaction.java:196)
2013-05-21 15:59:15,808 ERROR [STDERR] (pool-25-thread-2) ... 7 more
为什么会这样？