When you install a brand new Eclipse, in a brand new workspace, it find automatically the JRE, and fill the Execution environment.
But if you had latter a new JVM, it's not possible any more to add an execution environment.
The discovered path are wrong too, many jar are missing, and needs to be installed manually.
Does some one know how Eclipse build this list or how to force a re-discovery ?
I tried that with Eclipse 4.3, on Mac OS 10.8.4, trying to install JDK 1.7.0_40.