.??_  Files ending in "_" are often compressed install files of the same
          name (e.g., .EX_ expands to .EXE, .DL_ expands to .DLL, etc.)
  .J    Java Source Code
        JAR Compressed File
  .J2K  JPEG-2000 JP2 File  [XnView]
  .J62  Ricoh Digital Camera File
  .J6I  Ricoh Digital Camera File
  .JAG  Jaguar Server File (Atari)
  .JAR  Java Archive File (a compressed file for applets and related files)
  .JAS  Compressed Graphic
  .JAV  Java Source Code
  .JAVA  JBuilder Java File
  .JBC  Jam Byte-Code Hex File (8051 Microprocessor File)
        BestCrypt File
  .JBD  SigmaScan Data File
  .JBF  Paint Shop Pro Browser File  [XnView]
  .JBG  JBIG File  [XnView]
  .JBIG  JBIG File  [XnView]
  .JBK  Juno Backup File
  .JBP  DJ Jukebox Project
  .JBX  Project Scheduler File
  .JC!  FlashGet File
  .JD   Jigsaw Terminal File (Real-time financial data display)
  .JDB  Siren Jukebox
  .JDE  Cariverona
  .JDF  Turok 2 Game File
  .JDT  Accelio Capture Classic (JetForm) Filler (JetForm Corp became Accelio 12 Sep 2001)
  .JDX  EDICT Index (EDICT is Japanese/English Dictionary)
  .JEF  Janome NH10000 Sewing Machine File
  .JET  Hybrid JetFax Fax
  .JFD  FormWare Job
        JAWS Voice Synthesis Software
  .JFF  JPEG Image
  .JFI  JPEG/JIFF Image  [XnView]
  .JFIF  JPEG/JIFF Image  [XnView]
  .JFM  Accelio Capture Classic (JetForm) File (JetForm Corp became Accelio 12 Sep 2001)
  .JFX  J2 Fax File
  .JG6  BigJig Jigsaw
  .JHTML  Dynamo Server Page (Java HTML)
  .JIF  JPEG/JIFF Image  [XnView]
        Jeff's Image Format  [XnView]
  .JIS  Japanese
  .JLF  JetLinks Bookmark Managment
  .JLS  JPEG-LS File  [XnView]
  .JMP  SAS JMPDiscovery Chart-to-statistics File
  .JMS  Voxtron TeleButler Graphical Voice Response Call Flow
  .JMX  JMeter File (Web performance testing)
  .JN1  Epic MegaGames Jill of the Jungle Data File
  .JNB  Sigma Plot Workbook File
  .JNG  JPEG Network Graphic  [XnView]
  .JNK  Junk (temporary file)
  .JNL  Ingres Journal File
  .JOB  Job File
        Task Scheduler Task Object
        AI Research File
        QuestVision Vector Graphics File (IMG File Conversion)
  .JOBOPTIONS  Acrobat Job Options File
  .JOD  Microsoft.Jet.OLEDB.4.0 Related File
  .JOR  MS SQL Server Journal File
  .JOT  WinJottr Desktop Note
        JDesignerPro File
  .JOU  VAX Edt Editor Journal Backup
  .JP2  JPEG-2000 JP2 File  [XnView] [Kakadu]
  .JPC  Picture File (Japanese)
        JPEG-2000 Code Stream  [XnView]
  .JPE  JPEG/JIFF Image  [XnView] [IrfanView]
  .JPEG  JPEG/JIFF Image  [XnView] [IrfanView]
  .JPG  JPEG/JIFF Image  [XnView] [IrfanView]
  .JPL  Siren Jukebox
  .JPS  Stereo Image  [XnView]
  .JPX  JBuilder Project File
        JPEG-2000 JP2 File  [XnView]
  .JS   JavaScript Source Code
  .JSB  Henter-Joyce, Inc. Jaws Script Binary File (Screen reader program)
  .JSD  eFAX Jet Suite Document
        Henter-Joyce, Inc. Jaws Script Documentation File (Screen reader program)
        Join-Split File
  .JSE  JScript Encoded Script File
  .JSF  Macromedia Fireworks Batch Script
  .JSH  Henter-Joyce, Inc. Jaws Script Header File (Screen reader program)
  .JSL  PaintShop Pro File
  .JSM  Henter-Joyce, Inc. Jaws Script Message File (Screen reader program)
  .JSP  Java Server Page
  .JSS  Henter-Joyce, Inc. Jaws Script Source File (Screen reader program)
  .JT   JT Fax
  .JTD  Ichitaro 11 (major Japanese word proccesser)
  .JTF  JPEG Tagged Interchange Format Image
        Hayes JT Fax  [XnView]
  .JTK  Sun Java ToolKit File
  .JTP  JetForm File
  .JVC  Digital Camera File
  .JW   Justwrite Text
        Jigsaw Terminal File (Real-time financial data display)
  .JWL  Justwrite Text File Library
        Easy CD Creator's CD Label
  .JWP  JWP Document (Japanese word processor)
        Easy CD Creator Label File
  .JZZ  Jazz Spreadsheet