J
| Ext. | Description | Used by |
|---|---|---|
| J2C | JPEG 2000 image | |
| JAM | Jam messagebase | FTN software |
| JAM | Jam music score | Jam |
| JAR | Java archive | JAR, Java Games and Applications |
| JAS | see JASC | |
| JASC | Graphics format (JASC) | |
| JAV | see JAVA | |
| JAVA | Java source code file | |
| JBD | Datafile | SigmaScan |
| JBIG | Joint Bilevel Image Group | |
| JBX | Project file | Project Scheduler 4 |
| JCN | JobClock.Net Synch File | |
| JET | Fax | Hybrid JetFax |
| JFF | see JFIF | |
| JFIF | JPEG File Interchange Format | |
| JIF | see JFIF | |
| JMS | Music format (JMusic file) | UltraForce |
| JOB | Gravostyle engraving pattern file | Gravostyle/Gravograph |
| JOB | QUEUE output file | RT-11 |
| JOR | Journal file SQL | |
| JOU | Journal backup | VAX Edt editor |
| JP2 | JPEG 2000 image | |
| JPC | Graphics | Japan PIC |
| JPEG | Joint Photography Experts Group graphics file format | QPeg - FullView - Display |
| JPG | see JPEG | |
| JPS | backup of startup files (AUTOEXEC.BAT,CONFIG.SYS,4DOS.INI) by installation of 4DOS (JP Software) | 4DOS |
| JRE | Java Runtime Environment | Java |
| JRN | JMP journal | JMP |
| JSON | JSON (JavaScript Object Notation) | Ajax |
| JSP | JavaServer Pages | Dynamic pages running Web servers using Java technology |
| JS | JavaScript file | script in HTML pages |
| JTF | Fax | Hayes JT Fax |
| JTF | Graphics (TIFF file with JPEG compression) | |
| JVX | Data | JavaView object |
| JW | Text document | JustWrite |
| JWL | Library | JustWrite |
| JZZ | Spreadsheet | Jazz |
Read more about this topic: List Of File Formats (alphabetical)