Hi! based on Andrew P. suggestion I bumped the version of JDK6 to the latest update (45) and it seems to have cured the HBase problem.
As a side note: for a deprecated, unsupported platform such as JDK6 there's no reason to use anything but the latest version anyway. But even with that, we still do have quite a few failures in various components (Hive, Pig, etc.). How do we attack it? Thoughts? Thanks, Roman.