Saros is a Eclipse plugin for collaborative text editing that in particular targets distributed pair programming (also called remote pair programming), but can support arbitrarily many participants at once. All members of a session have an identical copy of an Eclipse project and Saros keeps these copies in sync as editing progresses.
EMF Validation Builder is an Eclipse plugin that automates the validation process at the time of saving. This means that resource problem markers are up to date as soon as you save your model. A dependency table is maintained, which allows the validation process to be re-run when necessary. In particular, the tool can be directly used with ECore model files.