| .J | Oracle Corporation | Utviklerfiler | Java Source File | Adobe Photoshop | Adobe Systems Incorporated |
| .J2K | Joint Photographic Experts Group | Rasterbildefiler | JPEG 2000 Image | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JDF | Adobe Systems Incorporated | Innstillingsfiler | Adobe Acrobat Job Definition File | Adobe Acrobat DC | Adobe Systems Incorporated |
| .JDT | Adobe Systems Incorporated | Datafiler | Accelio Capture Classic Filler Data | Accelio Capture Classic Filler | Adobe Systems Incorporated |
| .JFI | Joint Photographic Experts Group | Rasterbildefiler | JPEG File Interchange Image | Adobe Photoshop | Adobe Systems Incorporated |
| .JIF | Joint Photographic Experts Group | Rasterbildefiler | JPEG Image | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JOBOPTIONS | Adobe Systems Incorporated | Datafiler | Adobe Joboptions File | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JP2 | Joint Photographic Experts Group | Rasterbildefiler | JPEG 2000 Core Image File | Adobe Photoshop Elements | Adobe Systems Incorporated |
| .JPC | Joint Photographic Experts Group | Rasterbildefiler | JPEG 2000 Code Stream File | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JPEG | Joint Photographic Experts Group | Rasterbildefiler | JPEG Image | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JPF | Joint Photographic Experts Group | Rasterbildefiler | JPEG 2000 Image | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JPG | Joint Photographic Experts Group | Rasterbildefiler | JPEG Image | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JPG-LARGE | Zoner Software | Rasterbildefiler | Large JPEG Image | Adobe Photoshop | Adobe Systems Incorporated |
| .JPG2 | Joint Photographic Experts Group | Rasterbildefiler | JPEG 2000 Image | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JPS | Open Source | Backupfiler | Akeeba Backup Archive | Adobe Photoshop CC | Adobe Systems Incorporated |
| .JPX | Embarcadero Technologies | Utviklerfiler | JBuilder Project | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JS | NetScape | Web-Filer | JavaScript File | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JSCRIPT | NetScape | Web-Filer | JavaScript File | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JSE | Microsoft Corporation | Eksekverbare filer | JScript Encoded File | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JSF | Adobe Systems Incorporated | Web-Filer | Java Script Command File | Adobe Fireworks | Adobe Systems Incorporated |
| .JSFL | Adobe Systems Incorporated | Utviklerfiler | Animate JSFL Script File | Adobe Animate CC 2017 | Adobe Systems Incorporated |
| .JSP | Oracle Corporation | Web-Filer | Java Server Page | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JSPA | Xinox Software | Web-Filer | Java Servlet Alias | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JSPF | Oracle Corporation | Utviklerfiler | Java Server Page Fragment | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JST | Jabosoft | Spillfiler | Jnes Save State | Adobe Dreamweaver | Adobe Systems Incorporated |
| .JSX | Adobe Systems Incorporated | Eksekverbare filer | ExtendScript Script File | Adobe After Effects | Adobe Systems Incorporated |
| .JTF | Various Developers | Rasterbildefiler | JPEG Tagged Interchange Format | Adobe Illustrator CC | Adobe Systems Incorporated |
| .JXR | Microsoft Corporation | Rasterbildefiler | JPEG XR Image | Adobe Photoshop | Adobe Systems Incorporated |
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