File extension	The full name of the file	Popularity
File extension J	Java Source File
File extension J2C	JPEG 2000 Code Stream
File extension J2I	Jazz 2 Internet Link File
File extension J2K	JPEG 2000 Image
File extension J2L	Jazz Jackrabbit 2 Level File
File extension J3O	jMonkeyEngine 3D Scene
File extension JA	Jet Archive
File extension JAC	JaStaCry Encrypted File
File extension JAD	Java Application Descriptor File
File extension JAG	Jagex Data File
File extension JAM	Leisure Suit Larry Magna Cum Laude archive file
File extension JAP	Japanese Nintendo 64 Game ROM
File extension JAR	Java Archive File
File extension JARPACK	Pack200 Packed Jar File
File extension JARVIS	Jarvis Subscriber File
File extension JAS	Corel PaintShop Photo Pro bitmap graphics file
File extension JASPER	JasperReports Data File
File extension JAV	Java Source File
File extension JAVA	Java Source Code File
File extension JB2	JBIG2 Image
File extension JBC	Jam STAPL Byte-Code File
File extension JBF	Paint Shop Pro Browser Cache File
File extension JBI	Motoman Robot Job File
File extension JBIG	Joint Bi-level Image Group File
File extension JBIG2	JBIG2
File extension JBK	Juno Backup File
File extension JBMP	JAmes OS Bitmap Image
File extension JBR	Paint Shop Pro Brushes File
File extension JC	FlashGet Partial Download
File extension JC!	FlashGet Incomplete Download
File extension JCLIC	JClic Project File
File extension JCP	Jesusonic preset file
File extension JCRYPT	JCRYPT File
File extension JCZ	Liquid Motion Animation
File extension JDB	Symantec Endpoint Protection Update File
File extension JDC	JDownloader Links File
File extension JDF	Adobe Acrobat Job Definition File
File extension JED	Xilinx JEDEC Programming File
File extension JEF	Janome Embroidery Format
File extension JFI	JPEG File Interchange Image
File extension JFIF	JPEG File Interchange Format
File extension JG4	BigJig Jigsaw Puzzle
File extension JGCSCS	EditPad Custom Syntax Coloring Scheme File
File extension JGW	JPEG World File
File extension JGZ	Gzipped Javascript File
File extension JHTML	Java HTML Web Page
File extension JIA	Digital Photo Navigator Album
File extension JIC	Java Icon File
File extension JIF	JPEG Image File
File extension JIFF	JPEG Image File Format
File extension JIGSAW	Jigsaw Explorer Save File
File extension JIS	Japanese Industry Standard Text
File extension JKM	JAWS Key Map File
File extension JL	Julia Source Code File
File extension JMP	JMP Data File
File extension JMV	Jnes Movie File
File extension JNG	JPEG Network Graphic
File extension JNILIB	JNI Library
File extension JNLP	Java Web Start File
File extension JNT	Windows Journal File
File extension JO	jo Audio File
File extension JO-7Z	jo Audio File
File extension JOB	Windows Task Scheduler Job File
File extension JOBOPTIONS	Adobe Joboptions File
File extension JOE	JOE Document
File extension JOINED	HJ-Split Data File
File extension JOY	CryENGINE Facial Editor Joystick File
File extension JP1	Japanese (Romaji) Text File
File extension JP2	JPEG 2000 Core Image File
File extension JPC	JPEG 2000 Code Stream File
File extension JPD	Java Process Definition
File extension JPE	JPEG Image
File extension JPEG	JPEG Image
File extension JPF	JPEG 2000 Image
File extension JPG	JPEG Image
File extension JPG2	JPEG 2000 Image
File extension JPGW	JPEG World File
File extension JPH	JProbe Memory Snapshot
File extension JPN	Windows Japanese Noise-Word List File
File extension JPR	JBuilder Project
File extension JPS	Stereo JPEG Image
File extension JPW	World File for JPEG
File extension JPX	JPEG 2000 Image File
File extension JRC	PCjr Cartridge ROM File
File extension JRPRINT	JasperReports Print File
File extension JRS	Exchange Reserve Transaction Log File
File extension JRTF	JAmes OS Rich Text File
File extension JRXML	JasperReports Layout File
File extension JRZ	PSP Game Data File
File extension JS	JavaScript File
File extension JSD	Jazer Data File
File extension JSDA	Jazer Data File
File extension JSE	JScript Encoded File
File extension JSF	Adobe Fireworks batch script
File extension JSFL	Flash JavaScript File
File extension JSH	JAWS Script Header File
File extension JSON	JavaScript Object Notation File
File extension JSP	Java Server Page
File extension JSPA	Java Servlet Alias
File extension JSPF	Java Server Page Fragment
File extension JSPX	XML Java Server Page
File extension JSS	JACOsub Subtitle File
File extension JST	JavaServer Page Document
File extension JSX	ExtendScript Script File
File extension JSXBIN	Binary ExtendScript Script File
File extension JSXINC	ExtendScript Included Script File
File extension JT	JT Open CAD File
File extension JTBACKUP	Just Type Backup File
File extension JTF	JPEG Tagged Interchange Format
File extension JTP	Windows Journal Template
File extension JTS	Cyberlink AVCHD Video File
File extension JTV	J. River TV File
File extension JTX	ESE Transaction Log
File extension JUDE	JUDE Project File
File extension JVS	JavaScript Proxy Autoconfig File
File extension JVSG	Video Surveillance Project
File extension JWL	Roxio Jewel Case File
File extension JWS	Java Web Services File
File extension JXR	JPEG XR Image