On this page you can download the compiled Java class files for JavaBoy, as well as the source code. The source code is only needed if you intend to recompile the emulator.

Source is available under the GNU general public licence, which can be found here, and is also included in the source archive.

Please note that a Java runtime environment is needed to run JavaBoy as an application, which is the preferred method. Links are provided here to the IBM Java Runtime Environment, which is recommended for good performance, although it is rather a hefty download. Make sure to download both files.

Sun's Java Runtime Environment can also be used, which comes in at a more reasonable 8Mb.

Title Size Release date
JavaBoy version 0.92 85Kb 18/06/05
JavaBoy version 0.92 source code 78Kb 18/06/05
JavaBoy version 0.91 79Kb 08/05/05
JavaBoy version 0.91 source code 71Kb 08/05/05
JavaBoy version 0.9 70Kb 25/03/05
JavaBoy version 0.9 source code 64Kb 25/03/05
JavaBoy version 0.81 65Kb 12/07/01
JavaBoy version 0.81 source code 60Kb 12/07/01
Sun Java Runtime Environment 1.5 ~8.0Mb -


Version 0.92

Emulation Changes

  • Fixed LCDC interrupt LCY flag. Fixes crash in 'Max', 'Rayman GBC', 'Donkey Kong Country'.
  • Fixed problem when grabbing the next instruction when executing right next to the end of memory. Fixes crahes on 'G&W Gallery 3', 'Millipede/Centipede' and others
  • Fixed P10-P13 interrupt handling. Fixes controls in Double Dragon 3 menus, Lawnmower Man, and others.
  • Added hack to unscramble status bars on many games (Aladdin, Pokemon Pinball) that change bank address just before the window starts
  • Changed sprite hiding behaviour. Now sprites are turned on if they're visible anywhere in the frame. (Elevator Action, Mortal Kombat 4)
  • Fixed debug breakpoint detection (Micro Machines 2, Monster Race 2, others)
  • Changed VBlank line to fix white screen on startup (Home Alone, Dragon Tales)
  • Added extra condition to LCD interrupts - that the display should be enabled.
  • Fixed comparison with LCY register, Austin Powers Oh Behave! now works, and GTA status bar isn't scrambled.
  • Fixed BG enable on GBC. Dragon Ball Z now works.
New Features
  • Added support for MBC3 mapper chip. MBC3 games now work (Pokemon Blue/Crystal/Gold/Silver, Harvest Moon)
  • Added emulation of the Game Boy Printer (only in application mode for now)
Applet mode changes (when running on a web page)
  • Fixed online save RAM bugs
Version 0.91

Applet Mode Changes (when running on a web page)

  • Switch menu from click to double-click to avoid problem with setting focus
  • Added Save to Web feature
  • Added reset option to menu
  • Fixed bad update to border when applet window covered (only on microsoft VM)
Emulation Changes
  • Fixed printing of HDMA data to console slowing down games
Version 0.9

Applet Mode Changes (when running on a web page)

  • Fixed ROMS with save RAM not loading when on a web page
  • Applets can be sized other than 1x
  • Applets show strip showing current ROM and other info displayed at start
  • Applets have options menu providing control change, size change, frameskip change, sound toggle
  • Applets have a parameter to turn sound on/off in the applet tag
Application Mode Changes (when running stand-alone)
  • Half-fixed keyboard controls sometimes not starting in application version
  • Fixed random keypressed causing an exception when no ROM loaded
General changes
  • ROMS can optionally be loaded from ZIP/JAR and GZip compressed files (code contributed by Stealth Software)
Emulation Changes
  • Much more accurate emulation of sound channel 4 (noise)
  • Flipped double height sprites are now handled properly


  • Corrected bug in LCDC register for hiding sprites
  • Fixed tile cache memory bug

Background graphics taken from The Legend of Zelda, Earthworm Jim, Gremlins 2, Tetris, Bubble Bobble, Super Marioland, Gradius 2, Bubble Ghost, Megaman, Super Marioland 3, Burger Time, Donkey Kong, Aladdin, Street Fighter 2, Spiderman.