I recently upgraded to Ganymede. Day before yesterday, I decided to
address all my compiler warnings. I noticed this one warning "No required
execution environment has been set." I attempted to heed the warning an
make the appropriated settings in the manifest. I was then rewarded a
cascading set of problems. Everyone of the plugins in my project ceased
to compile yeilding the message saying there was an access restriction on
rt.jar. According to the project properties under "java build path/JRE
System Library" there are no restrictions set. I then deleted the
required environment business from all manifests clicking the update
classpath thing as I went, but to no avail.
I cured the problem by selecting Alternate JRE in the JRE System Library
edit dialog and selecting the same JRE as was the workspace default. The
whole complaint about access restriction disappeared. Later, I used the
dialog to reset back to the workspace default and all remains well.
What gives?
PS
When I was in the throws of setting required environments, in one of my
plugins, no matter what I did I could not satisfy the need for an exact
match jre. From the Overview/Configure JRE associations... I would select
what the dialog would tell me was an exact match, but eclipse would
continue to say that it was not.