Uninstall OpenJDK

Guys, can somebody please clarify for me why you cannot uninstall OpenJDK using Synaptic ? Being a new user for this distribution, i do not yet know dependencies - i am assuming that there are some. Or, if there are none, it is a bug.
I need to install Oracle JDK - not by choice - i must have it in order to be able to work and i see no reason to have OpenJDK at the same time (although possible and not a deal breaker) - i like to keep my system as clean as possible.
Thanks in advance.

OS: Linux 3.8.0-23-generic x86_64
System: Netrunner 5 Enigma (13.06)
KDE: 4.10.3

Processor (CPU): Intel® Core™ i7-3770K CPU @ 3.50GHz
Speed: 1,600.00 MHz
Cores: 8

Total memory (RAM): 15.6 GiB
Free memory: 9.8 GiB (+ 4.3 GiB Caches)
Free swap: 16.0 GiB

Why can’t you remove OpenJDK ? What is the exact error you get ?

I don’t get any error. Every time i select for removal the openjdk 7 package, it automatically selects for installation openjdk 6. And there is no possibility of removing the selected for installation.
I can add some screen shots if that helps.

It seems that some package depends on either openjdk6 or 7 so it will automatically mark openjdk6 for installation if removing version 7.
What you could try is take a look at the packages that depend on openjdk. In Synaptic just go to properties of openjdk6 (or 7) -> dependencies and make sure to check in the dropdown menu that you selected packages depending on openjdk.

As an alternative there is always the possibility to install the far more advanced package manager aptitude here (only comes as cli app though) which allows for a more advanced resolution solving here which might also allow you to completely remove openjdk and its dependent package.

My mistake - i was looking at openjdk-7-jre-lib only, without looking for dependencies on openjdk-7-jre.
Sorry, i should have paid more attention first -

sudo apt-cache rdepends openjdk-7-jre gives me a long shopping list :angel:

Thanks a lot for taking the time to respond.