Mac OS X 10.9
java version "1.7.0_17"
Java(TM) SE Runtime Environment (build 1.7.0_17-b02)
Java HotSpot(TM) 64-Bit Server VM (build 23.7-b01, mixed mode)
Mac OS X Support
How it happened:
I had another version of jEdit (I guess jEdit 4) and Java 6 before and my jEdit was working fine.
Then I installed Java 7 but when I tried to run the jEdit it brought up an alert saying it needs Java SE 6 to run!
I did some search in the net, and it seems that jEdit 4.5 (and I guess jEdit 5.1 too!) should not have any issue with Java 7, so I got rid of the old version, downloaded jEdit 5.1.0 and installed it. I expected that it should work and don't bring up that complain alert BUT it didn't work and brought up *To open "jEdit.app," you need a Java SE 6 runtime.* complain again, it offers to install Java 6 too and if I select *Not now* (because I need Java 7) it closes the application.
I still could run jEdit using this command, but I can't use Ctrl+C & Ctrl+V shortcuts for copy and paste!
java -jar /Applications/jEdit.app/Contents/Resources/Java/jedit.jar
the first time that I ran this command, it brought up plugin manager up and said some of plugins (including Mac OS X Support) needs to be updated, and so I updated them.
I don't think Activity log has any useful information in this case, because program is closed before it got started.