I'm try to rebuild jruby's src.rpm from jpackage.org (JPP-1.7) and build fails on line 18 in test/testTime.rb: test_equal(Time.now.dst? ? 1 : -1, t3 <=> t4) This line is depend on configuration of a build system and not work properly, if the timezone (/etc/localtime, and /etc/sysconfig/clock) is default with implicit values. In that case the compare returns false. In system configured to any other zone (eg. CET), the test returns true. This behavior is the same as (c)ruby interpreter, and this is not a bug in jruby, but in jruby's unittest. Unfortunately I cannot configure the build system using specfile and the package have to be build in this kind of environment (but I attach the /etc/localtime and /etc/sysconfig/zoneinfo files). I can only create a patch to this test and comment these line, but it isn't the best approach (it's the best way with my poor knowledge about ruby ).