One error that has bugged my Eclipse PDT for a long time, was _org.eclipse.emf.ecore.util.EcoreEMap $DelegateEObjectContainmentEList. _A vague error, not much to go on, not many hits on google either. Turned out it had to do with the version of my Java Runtime Environment I was using.
Current Java Version in Use
You can check what Java Runtime version Ubuntu is using by entering:
$ java -version
In my case, it resulted in the following output
java version "1.5.0" gij (GNU libgcj) version 4.2.3 (Ubuntu 4.2.3-2ubuntu6) Copyright (C) 2007 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
Even though I have the original Sun Runtime installed:
$ dpkg -l |grep jre ii sun-java6-jre 6-07-3ubuntu2 Sun Java(TM) Runtime Environment
It was not being used. It was before. I don't know what changed it.
Available Java Versions on System
To change it back, I used
$ sudo update-java-alternatives -l
to show me what candidates were available:
java-6-sun 63 /usr/lib/jvm/java-6-sun java-gcj 1042 /usr/lib/jvm/java-gcj
Change Java Version
I really want to change it back to Sun's version, so I run
$ sudo update-alternatives --config java
Which will show me
There are 4 alternatives which provide `java'. Selection Alternative ----------------------------------------------- 1 /usr/bin/gij-4.2 2 /usr/bin/gij-4.1 *+ 3 /usr/lib/jvm/java-gcj/jre/bin/java 4 /usr/lib/jvm/java-6-sun/jre/bin/java Press enter to keep the default[*], or type selection number:
So I press 4
And this gives me:
Using '/usr/lib/jvm/java-6-sun/jre/bin/java' to provide 'java'.
Confirm Java Version
To confirm it is really used, I ask Java it's version again:
$ java -version
java version "1.6.0_07" Java(TM) SE Runtime Environment (build 1.6.0_07-b06) Java HotSpot(TM) Server VM (build 10.0-b23, mixed mode)
Alright, all did go well. When I run Eclipse PDT again, all of my errors are gone.
Thank you Ubuntu