In org.hibernate.engine.transaction.Isolater.JtaDelegate.delegateWork, we find this code:

...
finally {
if ( surroundingTransaction != null ) {
try {
transactionManager.resume( surroundingTransaction );
if ( log.isDebugEnabled() ) {log.debug( "surrounding JTA transaction resumed [" + surroundingTransaction + "]" ); }
} catch( Throwable t ) {
if ( !caughtException ) {
new HibernateException( "unable to resume previously suspended transaction", t );
}
}
}
}

The last line should probably be
throw new HibernateException( "unable to resume previously suspended transaction", t );

• currently, any exception thrown by resume() will be silently eaten.