JMupen is a Java GUI for Mupen64plus (N64 Emulator), it is multiplatform (so it will run on Windows, Mac and Linux).
Latest version is hosted under http://xela92.linuxzogno.org/JMupen and is named JMupen.jar (you can also find it under exe folder in this source)
This software includes binaries from https://github.com/mupen64plus/mupen64plus-core/releases/tag/2.5 and from http://www.mupen64plus.org/old-releases/
It is a just-for-fun project, so I can't guarantee support. In case of problems, submit me an issue and I will fix it when possible, if possible.
If you don't mind sources, go to exe directory and grab JMupen.jar. To run it, just double-click on it. If it's not working, please install Java 8 ( www.java.com ).
Linux Users: if it's not working please resolve dependencies. You need to install sdl(1.2), libpng14, freetype, zlib, (lib)glu, libboost. If you use Archlinux, under src/bin_legacy/lin/lib/ (in jar file or in these sources) you can find a script named "jmupen_deps_arch.sh". If you run it in that folder, it'll solve dependencies for you (needs to be tested).
As it is Mupen, when you're in game commands are the same of Mupen64plus. See Wiki for additional details.