[ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1869?page=c... ] Stephen Hiley commented on HHH-1869: ------------------------------------ This is one of those insidious bugs, as it does not blow up at runtime, but instead returns the wrong value. We were burned by this in our production environment. The code fix offered by the reporter here is spot on! The number being loaded into hival from doWorkInNewTransaction() should be a long. And the following multiplication should be cast for clarity as shown in the attached version. Offending code: org.hibernate.id.MultipleHiLoPerTableGenerator hi = hival * (maxLo+1); where hival and maxLo are both ints. The result, hi, is a long. But that doesn't matter to java when it does the computation. It computes the result as an int, overflows the max lengh, then casts the result to along. To fix, one just needs to cast the result explicitely, or change hival to be a long (see bug reporter's code). Here's the JUnit test I wrote to prove this. @Test public void testIntToLong() { int hival = 34550207; int maxLo = 5000; long uncastHi = hival * (maxLo + 1); long expectedHi = (long) hival * (maxLo + 1); assertEquals("Wishing these two results matched!", expectedHi, uncastHi); } Yields: junit.framework.AssertionFailedError: Wishing these two results matched! expected:<172785585207> but was:<986893367> The test fails, demonstrating the bug in the generate() method. Interestingly, this problem was not duplicated in the TableHiLoGenerator in the same package, in that it sets the return value of the super.generate() as a long. long val = ( (Number) super.generate(session, obj) ).longValue(); But it does suffer from treating that returned hival from the database as an Integer, which will suffer the same truncation problems once your hival grows beyond the max size of a java int. Perhaps this should be handled as a seperate bug. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.... - For more information on JIRA, see: http://www.atlassian.com/software/jira