Dpkg error when trying to uninstall java

Question

I have been trying to uninstall jre6 but I keep getting the error
dpkg: warning: there's no installed package matching sun-java6-jre:amd64
I've tried
sudo apt-get --purge remove sun-java6\* vim
and
sudo apt-get purge sun-java6-\* I just want to remove it so I can install JDK7.

Answer 1

First off, I believe the uninstall is failing because you don't have the package name exactly right. You do not need to uninstall the old version as there is a way for you to choose which you would prefer to use. Enter this command in terminal:

sudo update-alternatives --config java

The versions of Java currently installed on your system will appear for you to choose from. Keeping both can come in handy as some applications may work better with one or the other. After you have made your choice, enter this command in terminal:

java -version

That will tell you which version is currently in use to confirm your changes

Answer 2

If you ever get a dpkg error. Use the following to purge to dpkg (this is an extreme measure)
sudo dpkg -P sun-java6-jre
This should delete all remnants of sun-java6-jre .