Currently Eclipse uses ~/.eclipse for configuration and data files. It would be great if we could change it to follow the XDG Base Directory Spec http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html. There are a number of advantages to this including making it much easier to migrate data across systems or during upgrades.
Eclipse doesn't make a clean difference between config, cache, data and runtime data. Wherever we choose to put this data it should be in a single directory because the layout of ~/.eclipse folder is the same on all platforms and not all of them expose xdg variables. As most of the data in ~/.eclipse is installation specific we would need to put it in $XDG_DATA_HOME, am I right? Additionally Eclipse doesn't support reusing metadata from previous version and if it's put data_home we will not gain anything. I'm all for following XDG Directory Spec but this requires working with upstream to get it fixed and I won't be able to work on that anytime soon. Help is more than welcome!
We should file this upstream (I'm guessing Equinox but it'll involve lots of teams): https://bugs.eclipse.org/bugs/enter_bug.cgi?product=Equinox&component=Framework
Closing as this would not be accepted upstream and there is even noone that would spend the huge amount of work on that.