clever(er) file merging tools?

["Nigel Magnay" <nigel.magnay@gmail.com>]

This isn't git-specific, but since git users tend to merge more often
there might be some good knowledge here.

My usual practice in merging is to issue the merge, then use 'git
mergetool' to cope with conflicts. On my mac, that fires up opendiff,
which does a reasonable (I guess) attempt at unpicking the changes and
allowing me to choose.

Sometimes, however, probably due to complexity, it spits out a huge
section of the file as being in conflict. Examining it, I always end
up getting annoyed, since for a lot of the file, the changes aren't in
conflict at all - whole (java) functions are in the conflict area
where they're actually the same.

I have wondered if I could pre-filter the sourcecode through something
like Jalopy to re-order all the blocks into a common ordering. But I
also wondered if there were any merge tools that (say) understand the
structure of Java and use it to compare at a method declaration level
rather than as a big text document? Maybe just opendiff isn't the best
(though I quite like the interface as it's easy to understand and the
price is right...)