1.6.08 is fine and behaving as expected.

I upgraded to 1.6.13 which I believe is the first version enforcing a dependency on Java 7. Your repository still depends on Java 6 components. This is my /etc/apt/sources.list

deb http://pkg.jenkins-ci.org/debian binary/

I therefore chose to apt-get remove openjdk-6-jre-headless after installing openjdk-7-jre-headless. This removed Jenkins and I reinstalled it. Jenkins should not depend on openjdk-6-jre, especially as trying to start with this version leaves an error in jenkins.log.

What I did not expect was for the contents of JENKINS_HOME (/var/lib/jenkins) to be removed on a remove. This was an apt-get remove but not a --purge. I believe this violates the Debian Packaging Policy.

After restoring to an earlier backup, I had 1.6.08 working again. I upgraded to 1.6.13 and installed Java 7. I had to run update-java-alternatives to get Java 7 set as the default.

Now, when I can finally load the Jenkins page, I see that the slaves are not starting. This is because they are using Java 6. I have an Oracle key specified for automatic installation of Java on remote systems. Therefore I can only conclude that the Ubuntu / Debian deployments of Jenkins are broken: they do not set the proper dependencies and they are not upgrading slaves on 6.x series either.

Please fix or verify:

That apt-get remove is safe! It should not remove configuration files, or in fact, any modified files.
Java 6 should no longer be a dependency for the Jenkins package
Jenkins should try and upgrade slaves to 7.x

I am gravely concerned Jenkins is planning another move to 8.x soon enough.

S