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 PURPOSE.

Even though I have the original Sun Runtime installed:

root@jade:/home/kevin# dpkg -l |grep jre
ii  sun-java6-jre    6-07-3ubuntu2    Sun Java(TM) Runtime Environment (JRE) 6

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

Telling me:

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

Stay up to date

You can track my blog articles and comments. You may also find my bookmarks interesting. Or Follow me on Twitter