I'm running the community edition of Alfresco and trying to get the Module Mgmt Tool to work. I keep getting an error "unsupported major.minor version 51.0" does anyone know what version is supported with 4.2 and where I can find it?
I suspect you are trying to use the MMT that ships with 4.2 and was built with Java 1.7 but locally you are running with Java 1.6. Please do a java -version to ensure you are running 1.7 which is required for Alfresco 4.2.
The problem is that you can't get Java 1.7 through apt-get yet, so it needs to be downloaded directly from Oracle. This is a script that does that, and adds an apt repo to keep it up to date.