Good news first: I already have the patch ready for that.
I got several TAR files which I could not extract with any of the existing Java implementations, but I could extract all those TAR files successfully with GNU tar.
It turned out that all the failing TAR files contained so called sparse files. Investigating the source code of all existing Java TAR implementations showed me that none of them even recognizes the existence of GNU sparse entries.
Actually, I don't need to process one of the contained sparse files and I'm happy if I'm at least able to correctly untar all the non-sparsed files. Thus, it would be sufficient recognizing sparse files without the need to correctly un-sparse them while extracting. As long as all non-sparsed files get extracted correctly, I'm fine.
The TAR files in question have all been VMware Diagnostic File bundles.
See http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=653 to know how to get them.