Oracle has decided to concentrate on entering the cloud computing market, competing against Amazon, Google and Microsoft and to do this, they’ve decided to make Java EE (Enterprise Edition) fully open source: https://blogs.oracle.com/theaquarium/opening-up-java-ee
We believe that moving Java EE technologies including reference implementations and test compatibility kit to an open source foundation may be the right next step, in order to adopt more agile processes, implement more flexible licensing, and change the governance process. We plan on exploring this possibility with the community, our licensees and several candidate foundations to see if we can move Java EE forward in this direction.
Sometimes, when a vendor open sources a proprietary project, it amounts to abandonment of that project, leaving the community or other smaller vendors to pick up the pieces.
Java EE is popular enough that IBM and Red Hat are huge supporters and seem to be willing to take up the reins of developing Java EE further.