Opening JJ Files

The JJ file type is primarily associated with JavaCC.

JJ	File extension: JJ
	File type:	source code file

What is a JJ file?

JJ files mostly belong to JavaCC. JJ files are mostly JavaCC grammar files.: These files contain the grammar rules, token declarations, and parser production instructions used by the JavaCC parser generator. They are written in plain text so that developers can edit them directly using any text editor. Once edited, the JavaCC tool processes the file and produces Java source code that implements the defined language syntax.
In some cases, a JJ file might not be a grammar file at all. If the file is binary and opens with image software like Adobe Photoshop, it may instead be a JPEG image.
Key details compiled by FilExt.com include:

Editing: Open with a text editor to view and modify grammar definitions.

Compilation: Process the file with the JavaCC tool to generate Java code.

Identification: Check whether the content is human-readable (indicating a grammar file) or binary (indicating an image).

FilExt.com note: For further technical details, visit the JavaCC website.

How to open JJ files

You need a suitable software like JavaCC to open a JJ file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your JJ file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a JJ file directly in the browser:. Just drag the file onto this browser window and drop it.

Online JJ File Viewer

Choose your .jj file to view this image

or drag and drop it here

Online File Viewer

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How to convert a JJ file to JPG, PDF, HTML, DOC, ...

If you want to convert or edit a JJ file, you can use our free Online JJ File Converter (powered by Convert.Guru):

To do so, click the "Choose your .jj file to view this image" button above.
Your JJ file will then be displayed in the browser.
Now click on "Save as..." at the top of the page.
Then click the file format (e.g. PDF, JPG, DOCX, TXT, ...) you want.
Your file will be converted and downloaded.

Programs that open and convert JJ files:

JavaCC
See the previous paragraphs to learn more about the main application. JJ files are often referred to as JavaCC developers because this type of file is primarily created or used by this software.
C64 Doodle Compressed File
Related links: XnView
JavaCC File
(Java parser generator)

Technical Data for JJ File Extension

File classification:

Developer

Related files:

jjt, cup, bnf, y, java, rmvb, txt, jpg, tpz, tdo, tzb

Related links:

XnView

Mime type:

application/octet-stream

The following listing is compiled from the database produced by the 'Associate This!' program, selected data from the main FILExt database and file extension information submitted by users.

ProgramID: GraphicsConverterPro.jj, FileType: Doodle C64 Compressed, AppName: GraphicsConverter-reg
EXEFile: GraphicsConverter.exe

ProgramID: XnView.Image
EXEFile: %ProgramFiles%\XnView\xnview.exe %1

a jj source code file is a special file format and should only be edited and saved with the appropriate software.

How to solve problems with JJ files

Associate the JJ file extension with the correct application.
Update your software that should actually open source code files. Because only the current version supports the latest JJ file format. Search, therefore, e.g. on the manufacturer website after an available JavaCC update.
To make sure that your JJ file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
Click here to open your .JJ file online - secure, fast, and no downloads needed.