CTXT File

What are CTXT files and how to open them

Are you having problems opening a CTXT file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CTXT files.

What is a CTXT file?

A .CTXT file is a BlueJ Class Context file.

BlueJ Class Context files are auxiliary metadata files used by the BlueJ Java IDE to help the environment keep track of extra information about each class apart from its source code or compiled form. They are created automatically during compilation after compiling a specific class. They store details like documentation comments, method signature targets, parameters, and the association between comments and methods in the class.

These files enable BlueJ to enhance the user interface: for example, by showing comment structure alongside code, or providing a richer context when browsing class diagrams. BlueJ writes them, keeps them in the same directory as the corresponding compiled .class file, and updates them each time the class is recompiled. Each Java class in a BlueJ project has one Class Context file.

Internally, a BlueJ Class Context file begins with a signature line #BlueJ class context and contains named fields such as comment0.target, comment1.params, comment1.target, numComments, etc., that map comments or documentation structures to specific methods or parts of the class. These strings help BlueJ identify which comments belong where in a class.

How to open CTXT files

Important: Different programs may use files with the CTXT file extension for different purposes, so unless you are sure which format your CTXT file is, you may need to try a few different programs.

While we have not verified the app ourselves yet, our users have suggested a single CTXT opener which you will find listed below.

Last updated: September 19, 2026

Various apps that use files with this extension

These apps are known to open certain types of CTXT files. Remember, different programs may use CTXT files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about CTXT file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.