Le estensioni dei file iniziano con il carattere 'J'
| Tipo di file | Categoria | Formato del file | |
|---|---|---|---|
| .j | Development Files | File sorgente Java | |
| .jad | Multiple Use Files | Java Application Descriptor File | |
| .jam | CAD Files | Jam STAPL File | |
| .jar | Program Execution Files | Java Archive File | |
| .jasper | Data Files | File JasperReports dati | |
| .jav | Development Files | File sorgente Java | |
| .java | Development Files | Java codice sorgente File | |
| .jbi | Data Files | File Motoman Robot lavoro | |
| .jdb | Data Files | Symantec Endpoint Protection file di aggiornamento | |
| .jdc | Backup Files | JDownloader Links File | |
| .jef | Data Files | Formato Janome ricamo | |
| .jfif | Raster Graphics Files | File JPEG Interchange Format | |
| .jgz | Compressed Files | File compresso con gzip Javascript | |
| .jic | Compressed Files | Java Icona File | |
| .jis | Text Files | Testo giapponese Industry Standard | |
| .jmp | Data Files | File JMP dati | |
| .jnilib | Development Files | JNI Biblioteca | |
| .jnlp | Java Files | Java Web Start File | |
| .jnt | Microsoft Files | Windows Journal File | |
| .jo | Audio Files | jo file audio | |
| .joined | Data Files | File HJ-Split dati | |
| .jp1 | Text Files | Giapponese (Romaji) File di testo | |
| .jp2 | Raster Graphics Files | JPEG 2000 core File Immagine | |
| .jpc | Raster Graphics Files | JPEG File 2000 Codice flusso | |
| .jpd | Development Files | Java Definizione processo | |
| .jpeg | Raster Graphics Files | JPEG Immagine | |
| .jpg | Raster Graphics Files | JPEG Immagine | |
| .jpg2 | Raster Graphics Files | JPEG 2000 Immagine | |
| .jpgw | Graphics Files | File JPEG mondo | |
| .jps | Raster Graphics Files | Stereo immagine JPEG | |
| .jrprint | Data Files | JasperReports Stampa file | |
| .jrtf | Text Files | James OS Rich Text File | |
| .jrxml | Data Files | JasperReports file di layout | |
| .js | JavaScript Files | File JavaScript | |
| .jse | Program Execution Files | JScript file codificato | |
| .json | JavaScript Files | JavaScript Object Notation File | |
| .jsp | Java Files | Java Server Page | |
| .jsx | Program Execution Files | ExtendScript Script File | |
| .jude | Data Files | File JUDE progetto | |
| .jws | Java Files | Java Web Services File |