You will never find JJ3d in google, but there are always other ways for search files...
I'm sure J2E editor does not exist. There's just a way, to modify the already maded J2E files. For example, you can make a copy one of them, renami it, and change the name of it, in hex editor, and the filename of the starting level. That's pretty easy. And I know there must be a way to change pictures in the J2E too.
These are the stuffs I'm already been tried to open it, and didn't worked:
- Renamed it to zip, and tried to extract.
- Try to open as an image with Ifranview
- The same, but before it, I've removed the first few rows with hex editor.
- Renamed it to j2t.

There must be an other way, and I'm sure, that's an easy way, just needs to find out... And maybe I'm not right, and was a j2e editor, for private release, but I'm not sure about it, since none from the community able to tell who made that j2e editor...