| File extension Name |
extension description |
| .J | JPEG / JFIF Image |
| .J | JAR Compressed File |
| .J | Java Source Code (Sun) |
| .J1 | EDIT Compiler JEDEC Boundary File |
| .J2A | Jazz Jackrabbit 2 Animation Library (Epic MegaGames Inc.) |
| .J2B | Jazz Jackrabbit 2 Music File (Epic MegaGames, Inc.) |
| .J2D | Jazz Jackrabbit Data File (Epic MegaGames, Inc.) |
| .J2E | Jazz Jackrabbit 2 Episode File (Epic MegaGames, Inc.) |
| .J2G | J2 Fax File |
| .J2H | Jazz Jackrabbit 2 High Scores (Epic MegaGames, Inc.) |
| .J2I | Jazz Jackrabbit 2 Internet Server Link (Epic MegaGames, Inc.) |
| .J2K | JPEG-2000 JP2 File |
| .J2L | Jaxx Creation Station Level File (Epic MegaGames Inc.) |
| .J2M | Jazz Jackrabbit 2 Recorded Macro (Epic MegaGames, Inc.) |
| .J2S | Jazz Jackrabbit 2 Language Data (Epic MegaGames, Inc.) |
| .J2T | Jazz Jackrabbit 2 Tile Set (Epic MegaGames, Inc.) |
| .J2V | Jazz Jackrabbit 2 Cinematic File (Epic MegaGames, Inc.) |
| .J62 | Ricoh Digital Camera File |
| .J6I | Ricoh Digital Camera File (Ricoh Co., Ltd.) |
| .J92 | Javelin Configuration File (Minisoft Inc.) |
| .JA | IBM Tools Updater File |
| .JA | Trainz Railroad Simulator Game Content (Auran Games) |
| .JACKET | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JACKSUM | Jacksum Fingerprint (Dipl.-Inf. (FH) Johann N. Löfflmann) |
| .JAD | Java Application Descriptor File (Sun Microsystems, Inc.) |
| .JAG | Jaguar Server File |
| .JAIL | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAM | FTN Software Jam Messagebase |
| .JAM | Image Microprose |
| .JAM | JamTracker Music Module |
| .JAM | E-mail |
| .JAM | Joaquim-Andrew-Mats Message Base Proposal |
| .JAM | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAM2 | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAMMIX | Jammix Enhacer Music Transform File (Danilics Tibor) |
| .JAN93 | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAP | Fifa World Cup Game Data fe Art Legalscr File |
| .JAP | JAlbum Project File (Datadosen) |
| .JAP | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAPAN | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAR | JARCS Compressed Archive (JPMdL Archival System) |
| .JAR | Java Applet (Sun) |
| .JAR | Java Archive (Sun Microsystems, Inc.) |
| .JAR | JAR Archive (ARJ Software, Inc.) |
| .JARRE | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JAS | Paint Shop Pro Compressed Graphic (Corel Corporation) |
| .JASC | JAS Compressed Graphic |
| .JAU | Jauge |
| .JAV | Java Source Code (Sun) |
| .JAVA | Java Source Code (Sun) |
| .JAW | IchiTaro Web Japanese Extended WordProcessor (Justsystem Corporation) |
| .JB2 | JBIG2 Bitmap Graphic |
| .JBB | JobEditor32 Binary Job Data (Motoman Inc.) |
| .JBC | Jam Byte-Codec File |
| .JBC | BestCrypt Container (Jetico, Inc.) |
| .JBD | SigmaScan Data File |
| .JBF | Backup Now Backed Up File (JetSoft Corporation) |
| .JBF | Paint Shop Pro Browser Cache (Corel Corporation) |
| .JBG | JBIG File |
| .JBI | JobEditor32 ASCII Job Data (Motoman Inc.) |
| .JBIG | JBIG File |
| .JBIG2 | JBIG2 Bitmap Graphic |
| .JBK | Juno Backup File |
| .JBK | Jot + Notes Backup File for Older Version (King Stairs Software) |
| .JBL | Doom Scene Add-in (Id Software, Inc.) |
| .JBP | DJ Jukebox Project |
| .JBR | Paint Shop Pro Brush (Corel Corporation) |
| .JBX | Project Scheduler File |
| .JC | FlashGet Intermediate Download (Beijing Zhitongwuxian Tech, Ltd.) |
| .JC | Watcom Source File |
| .JC! | FlashGet Incomplete Download (Beijing Zhitongwuxian Tech, Ltd.) |
| .JCAMP | Misc |
| .JCB | CB-JCBrooke Song/Module |
| .JCC | Japan Crossword Dmitry Torshin Format File (EliteWare) |
| .JCC | Code Crusader Project Data (New Planet Software) |
| .JCD | FlashGet Download Database File (Beijing Zhitongwuxian Tech, Ltd.) |
| .JCE | JWPce (Glenn Rosenthal) |
| .JCF | JAWS for Windows Configuration File (Freedom Scientific) |
| .JCK | Liquid Motion JACK Scene Description |
| .JCL | Job Control Language IBM |
| .JCM | Java Commerce Message Commerce Message (Wallet) (Sun) |
| .JCP | Jesusonic Preset (Cockos Incorporated) |
| .JCS | Latest Bruker WinSpecEdit v3.08 JCAMP |
| .JCS | Flashget Script HTML Table |
| .JCV | Baseball/Golf Analyzer (JC Video Systems) |
| .JD | Jigsaw Terminal File |
| .JDA | Winphone Fax Send Journal |
| .JDB | Winphone Fax Receive Journal |
| .JDB | Norton AntiVirus Update File (Symantec Corporation) |
| .JDB | Siren Jukebox |
| .JDBG | Project JEDI Embedded JCL Debug Information (Project JEDI) |
| .JDE | Cariverona |
| .JDF | Turok 2 Game File |
| .JDF | JAWS for Windows Voice Synth File (Freedom Scientific) |
| .JDF | Job Definition Format Job File |
| .JDT | Capture Classic Filler (Accelio) |
| .JDX | EDICT Index |
| .JDX | J Database Exchange (JDX) O/R Mapping Specification (Software Tree, Inc.) |
| .JDX | JCAMP Chemical Spectroscopic Data Exchange Format (MDL Information Systems, Inc.) |
| .JDX | JSpell UNICODE Dictionary (Page Scholar Inc.) |
| .JED | Xilinx Integrated Software Environment Device Configuration Information (Xilinx, Inc.) |
| .JED | JEDEC Programming Specification |
| .JEF | Janome NH10000 Sewing Machine Stitch File (Janome America, Inc.) |
| .JEQ | Jet Audio Saved Equalizer Setting (JetAudio, Inc.) |
| .JESD | JZEasyText Word Processor Save File (JamesZhu Inc.) |
| .JET | Hybrid JetFax Fax |
| .JET | Jetpack User-created Level Map |
| .JFD | JAWS for Windows (Freedom Scientific) |
| .JFD | FormWare Job |
| .JFF | JAWS for Windows (Freedom Scientific) |
| .JFF | JPEG Image |
| .JFG | jEEPers User Specific Information |
| .JFI | JPEG/JIFF Image |
| .JFIF | JPEG/JIFF Image |
| .JFM | Capture Classic (Accelio) |
| .JFX | J2 Fax File |
| .JG6 | BigJig Jigsaw (Lena Pankratova) |
| .JGCSCS | EditPad Pro Custom Coloring Scheme (JGsoft - Just Great Software) |
| .JGD | Paint Shop Pro Gradient (Corel Corporation) |
| .JGF | JAWS for Windows Configuration File (Freedom Scientific) |
| .JGF | Jetcam Geometry File (JETCAM International, Ltd.) |
| .JGL | QWS3270 PLUS Session Layout File (Jolly Giant Software Inc.) |
| .JGP | QWS3270 PLUS Session Parameter File (Jolly Giant Software Inc.) |
| .JGS | QWS3270 PLUS Script (Jolly Giant Software Inc.) |
| .JGW | Map File |
| .JHTM | Dynamo Server Page |
| .JHTML | Dynamo Server Page |
| .JIF | JPEG/JIFF Image |
| .JIF | Jeff's Image Format Bitmap |
| .JIG | Jigsaw Game (GameHouse, Inc., a division of RealNetworks, Inc.) |
| .JIG | Living Scenes Jigsaw Puzzles (Carolina Road Software L.L.C.) |
| .JIGDO | Jigsaw Download Download Instruction File (Richard Atterer) |
| .JIM | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JINKS | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JIS | Japanese Industrial Standard Text File |
| .JJ | C64 Doodle Compressed File |
| .JJ | JavaCC File |
| .JJC | Canvas Compressed Audio File |
| .JJF | Jester Jugglor File |
| .JKL | Jedi Knight |
| .JKM | JAWS for Windows Configuration File (Freedom Scientific) |
| .JKS | keytool Java Keystore (Sun Microsystems, Inc.) |
| .JKS | Jedi Knight Backup |
| .JL | Sawfish Lisp-based Script |
| .JLA | VisualPro BMP Image |
| .JLAB | JLab Program Source Code (Linova) |
| .JLC | Sawfish Byte Compiled Lisp-based Script |
| .JLF | JetLinks Bookmark Managment |
| .JLP | JLIP Video Capture (Video Producer) Index Format Display (JVC) |
| .JLS | JPEG-LS File |
| .JLS | JAWS for Windows (Freedom Scientific) |
| .JMA | Super Nintendo NSRT Compressed Game (Nintendo) |
| .JMAN | Illum Source Irohaserver File |
| .JMD | Paint Shop Pro Image Map Settings (Corel Corporation) |
| .JMF | Java Multimedia File (Sun) |
| .JMG | 16 Bit Adaptive RLE Compressed Bitmap |
| .JMH | JPEG File Interchange Format |
| .JMK | Code Crusader Build Script (New Planet Software) |
| .JMM | Digital Camera Video Clip (JVC) |
| .JMP | SAS JMP Discovery Chart-to-Statistics File (SAS Institute Inc.) |
| .JMS | UltraForce Music Format |
| .JMS | SpamProx Blocking List (Dewqs' Tribes) |
| .JMS | Voxtron TeleButler Graphical Voice Response Call Flow |
| .JMX | JMeter File |
| .JN1 | Epic MegaGames Jill of the Jungle Data File |
| .JNB | SigmaPlot Workbook File (SYSTAT Software Inc.) |
| .JNC | Communication Log File |
| .JNG | JPEG Network Graphic Bitmap |
| .JNGL | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JNK | Junk |
| .JNL | Journal Macro Data File (Chosen Software) |
| .JNL | ISC BIND Journal File (Internet Systems Consortium) |
| .JNL | WINDEV Log File (PC SOFT) |
| .JNL | Ingres Journal File (Computer Associates International, Inc.) |
| .JNLP | Java Web Start (Sun Microsystems, Inc.) |
| .JNT | Windows XP Tablet PC Edition Journal (Microsoft Corporation) |
| .JOB | AI Research |
| .JOB | BETA 44 Job File |
| .JOB | File Invesigator Script Commands |
| .JOB | Systems Management Server (SMS) Job File (Microsoft Corporation) |
| .JOB | MicroSim PCBoard External ASCII Job File |
| .JOB | QuestVision Vector Graphics File |
| .JOB | Windows Task Scheduler Task Object (Microsoft Corporation) |
| .JOB | Survey Pro Job (Tripod Data Systems) |
| .JOB | MetaCAM Nest Job (Metamation, Inc.) |
| .JOB | Job File |
| .JOBOPTIONS | Acrobat Job Options File (Adobe Systems Incorporated) |
| .JOBS | VirtualDub Job Control File (Avery Lee) |
| .JOC | Context4 DOS Word Processor File |
| .JOCL | Java Object Configuration Language |
| .JOD | MS.Jet.OLEDB.4.0 Related File |
| .JOI | Xboard Join Conferences File |
| .JOINED | HJSplit Default Joined File (Freebyte.com) |
| .JOKE | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JONES | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JOR | SQL Server Journal File (Microsoft Corporation) |
| .JOR | Gupta SQLWindows Journal |
| .JOT | Jot + Notes Note Data File (King Stairs Software) |
| .JOT | WinJottr Desktop Note |
| .JOT | JDesignerPro File |
| .JOU | VAX Edt Editor Journal File |
| .JOURNAL | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JOY | Trackjoy GUS Tracker Module |
| .JOY | Joystick Calibration File |
| .JP2 | Jeoparty II Presentation (Matthew Hagaman) |
| .JP2 | JPEG-2000 JP2 File |
| .JP3 | Electric Quilt File |
| .JP4 | Electric Quilt File |
| .JP5 | Electric Quilt File |
| .JPA | JoomlaPack Joomla Installation Backup (fronzenFX) |
| .JPC | Japan Picture Format |
| .JPC | JPEG-2000 Code Stream Bitmap |
| .JPC | Jprobe Coverage Memory Snapshot (Quest Software Inc.) |
| .JPE | JPEG/JIFF Image |
| .JPEG | JPEG/JIFF Image |
| .JPEGENX | egis Encrypted JPEG File (HiTRUST Inc.) |
| .JPF | Biz Plan Pro Business Plan Contents (JIAN Tools For Sales, Inc.) |
| .JPF | Mass Center Main Mass Spectrometry Data (JEOL USA, Inc.) |
| .JPG | JPEG/JIFF Image |
| .JPG | CompactDRAW e-JPG Graphic (MediaChance) |
| .JPGENX | egis Encrypted JPG File (HiTRUST Inc.) |
| .JPG_T | JPG Image File |
| .JPH | Jprobe Memory Debugger Memory Snapshot (Quest Software Inc.) |
| .JPI | Jupiter Document (Elfin Sp. z o.o.) |
| .JPL | Jprobe Settings File (Quest Software Inc.) |
| .JPL | Siren Jukebox |
| .JPM | LuraDocument.jpm Compressed PDF File (Algo Vision LuraTech GmbH) |
| .JPN | Photomodeler Lite File |
| .JPOW | JPowered Java Bar Charts |
| .JPP | Jigsaw Puzzle Player Puzzle Definition (B&P Games B.V.) |
| .JPP | Jprobe Profiler Memory Snapshot (Quest Software Inc.) |
| .JPR | Javasockets File |
| .JPR | Oracle JDeveloper Model JProject |
| .JPS | Print Studio Graphic (Jolly, Inc.) |
| .JPS | Stereo Image |
| .JPS | Jigsaw Puzzle Player Puzzle Completion Status (B&P Games B.V.) |
| .JPT | Print Studio Template (Jolly, Inc.) |
| .JPT | Jprobe Threadalyzer Memory Snapshot (Quest Software Inc.) |
| .JPX | JBuilder Project File (Borland Software Corporation) |
| .JPX | JPEG-2000 JP2 File |
| .JQX | Windows Help Related File (Microsoft Corporation) |
| .JQZ | JQuiz Quiz File |
| .JR | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JR2 | FishSim Add-on (J.C.Spooner) |
| .JRC | Jrchive Compressed Archive |
| .JRF | winIDEA Workspace (Programming Project File) (iSYSTEM AG) |
| .JRF | The Jumbot Bot Level Navigation File |
| .JRL | Top Secret Crypto Gold Top Secret Journal File (TAN$TAAFL Software Company) |
| .JRL | BioWare Aurora Engine Journal (BioWare Corp.) |
| .JRP | Electric Quilt File |
| .JRP | Pg4uw Job Report File (Elnec s.r.o.) |
| .JRXML | JasperReports JRXML Report Definition (JasperSoft Corporation) |
| .JS | JetScript Output File |
| .JS | JavaScript Source Code |
| .JS | JACOsub Script |
| .JS | Mozilla (Netscape) Settings (Mozilla.org) |
| .JSB | JAWS for Windows Script Binary File (Freedom Scientific) |
| .JSB | JavaScript Bean (JSB) File |
| .JSCRIPT | GoLive JavaScript (Adobe Systems Incorporated) |
| .JSD | Paint Shop Pro Image Slice Settings (Corel Corporation) |
| .JSD | Join-Split File |
| .JSD | JAWS for Windows Script Documentation File (Freedom Scientific) |
| .JSD | eFAX Jet Suite Document (j2 Global Communications, Inc.) |
| .JSDB | JumpStart Database (Jumpstart-it.com) |
| .JSE | JScript Encoded Script File |
| .JSE | Fichier Encoded Javascript |
| .JSF | Macromedia Fireworks Batch Script |
| .JSF | Jahshaka Scene File (The Jahshaka Project) |
| .JSFL | Flash Javascript (Adobe Systems Incorporated) |
| .JSH | JAWS for Windows Script Header File (Freedom Scientific) |
| .JSL | Paint Shop Pro Shapes File (Corel Corporation) |
| .JSL | Visual J# Code (Microsoft Corporation) |
| .JSM | JugWin Jigsaw |
| .JSM | Jig ShapeMap (Steamboat Software) |
| .JSM | Gray Design Associates Jigsaws Galore Jigsaw File |
| .JSM | JAWS for Windows Script Message File (Freedom Scientific) |
| .JSML | JSim Markup Language File (University of Washington) |
| .JSN | Shield Now Shield File (JetSoft Corporation) |
| .JSON | JavaScript Object Notation |
| .JSON | Google Gears Manifest File (Google) |
| .JSON | Firefox Bookmark Backup (Mozilla) |
| .JSP | Java Server Page (Sun) |
| .JSP10 | Java Server Page (Sun) |
| .JSPA | WebWork Framework JSP Action |
| .JSPF | JSP Page Fragment (Sun) |
| .JSS | JugWin Jigsaw |
| .JSS | Gray Design Associates Jigsaws Galore Saved Game Jigsaw File |
| .JSS | JAWS for Windows Script Source File (Freedom Scientific) |
| .JSS | JSheet |
| .JST | Jnes Saved Game State File (JaboSoft) |
| .JST | Code Crusader Symbol Database (New Planet Software) |
| .JSV | VXML JavaServer Page |
| .JSV | Japanese Flash Card File |
| .JSV | HyperRail 3D Coaster Design Construction File |
| .JSV | Java Structure Viewer |
| .JSW | WML JavaServer Page |
| .JSX | After Effects Script File (Adobe Systems Incorporated) |
| .JT | JT Fax |
| .JTD | Ichitaro Document (Justsystem Corporation) |
| .JTF | Hayes JT Fax |
| .JTF | JPEG Tagged Interchange Format Image |
| .JTIF | JPEG Tagged Interchange Format Image |
| .JTK | Java ToolKit File (Sun) |
| .JTL | JTool Data File (Behavioral Health Quality) |
| .JTP | Windows XP Tablet PC Edition Journal (Microsoft Corporation) |
| .JTP | JetForm File |
| .JTR | Jelbert GeoTagger Location Database (Jelbert Consulting) |
| .JUDI | JudoScript Source Code File (JudoScript.COM) |
| .JUDO | JudoScript Source Code File (JudoScript.COM) |
| .JUL | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JUL | Inteliweb Program Registration and Validation (InVision Marketing, Inc. & Inteliweb.net) |
| .JUMP | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JUMP1 | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JUN14 | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JUP | Code Crusader User-Specific Project Preferences (New Planet Software) |
| .JURL | JustUrls Button File (Eastern Digital Pty. Ltd.) |
| .JUST | Unknown Apple II File (found on Golden Orchard Apple II CD Rom) |
| .JUT | Jutvision Scene |
| .JVC | Digital Camera File |
| .JVS | Jpeg Video Sequencer Sequenced JPEG Images |
| .JW | Justwrite Text |
| .JW | Q & A Write for Windows 3.0 |
| .JW | Jigsaw Terminal File |
| .JW | MS Wordpad, Works for windows v3.0 & 4.0 |
| .JW | Legacy Version 1.1 |
| .JWC | Jw_cad Data (Jiro Shimizu & Yoshifumi Tanaka) |
| .JWC | JewelCase Maker Saved File (NewTech Infosystems Inc.) |
| .JWL | Easy CD Creator's CD Label (Sonic Solutions) |
| .JWL | Justwrite Text File Library |
| .JWL | Jewel Case Creator CD Disc Case |
| .JWP | JWP Document |
| .JWP | Easy CD Creator Label File (Sonic Solutions) |
| .JWR | LegaSuite GUI J Walk Runtime File (Seagull Software Systems, Inc.) |
| .JWS | WebLogic Workshop Java Web Services (BEA Systems, Inc.) |
| .JXDM | Multi-Channel Server (MCS) Markup Editor Java Server Page with XDIME Markup/Java Code (Volantis Systems Ltd.) |
| .JXT | Daqarta Extended Audio Data (Interstellar Research) |
| .JXX | C++ Header File |
| .JZ | JamesZhu Internet Browser Database File (JamesZhu, Inc.) |
| .JZZ | Jazz Spreadsheet |