Issues on Raspberry Pi 2

[Gat10279]

As the description states, I am having issues running forge on my raspberry pi 2, which is odd considering it used to work. This is the the error message I get when I try running it from the terminal. (along with the command I used)

pi@raspberrypi ~ $ java -Xmx1024m -jar /home/pi/Desktop/forge-gui-desktop-1.6.4-jar-with-dependencies.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: forge/view/Main : Unsupported major.minor version 52.0
(Stuff that the forum thinks contains offsite links that it won't let me post, sorry.)
Could not find the main class: forge.view.Main. Program will exit.

What does this mean and how do I fix it? Help would be greatly appreciated. Thank you in advance.

*edit, It's also worth noting (and I forgot to mention) it is not due to updating Forge. The current version I have has worked before. Surprisingly well actually.

[friarsol]

Did you somehow install a different version of Java than the one you used to have? That's what it sounds like the error is saying, your Java version is too old.

[Gat10279]

It was actually after I supposedly updated Java. Keyword supposedly. I uninstalled the update and it worked perfectly fine.

[vinnie]

For curiosity, are you using raspbian as distro?