Tips to open CLASS file

Can't open the CLASS file? You are not the only one. Thousands of users face similar problems every day. Below you will find tips on how to open CLASS files as well as a list of programs that support CLASS files.

CLASS file extension

File Name Java Class Format
File Developer Oracle
File Category Developer Files

The CLASS file is supported on 4 operating systems. Depending on your operating system, you may need different software to handle the CLASS files. Below is a summary of the number of programs that support and open the CLASS file on each system platform.

Operating systems
  • 4
  • 2
  • 2
  • 0
  • 0
  • 0

What is CLASS file?

A .CLASS file is a programming file, more precisely a compiled JAVA source code. .CLASS files are not directly executable, they still need to be packed into a .JAR file. Usually, however, a larger number of .CLASS files are needed for this. They correspond to the different classes in object-oriented programming. JAVA Virtual Machine (JVM) installation is required to compile .JAVA (development code) files into the target format. JRE is enough to run it.

How to open CLASS file?

The main problem with Java Class Format is that the CLASS file is incorrectly associated with programs. This is manifested by the fact that CLASS files open in unusual applications or do not have an assigned program. This problem can be easily remedied.

The first thing you should do is just "doubleclick" on the CLASS file icon you want to open. If the operating system has an appropriate application to support it and there is also an association between the file and the program, the file should be opened.

Step 1. Install Apple Jar Launcher

An often overlooked issue is to make sure that Apple Jar Launcher is installed on the computer. This can be achieved by typing Apple Jar Launcher into the operating system search engine. If it is not, installation may solve the problem, as most applications create file associations during installation. Later in this article you will find a list of programs that can open CLASS files.

Step 2. Create association of Apple Jar Launcher with CLASS files

If, despite the installed application, the CLASS file does not start in the Apple Jar Launcher application, you must create a file association. This option is available from the level of Properties of a specific file available in the context menu. The displayed window will contain information about the program that supports this type of file. Changes can be made using the "Change" button. It may happen that in the next window there will be no appropriate program - however, this can be corrected with the "Browse" option where you should manually indicate the program location. Checking the "Always use the selected program ..." box will permanently associate the CLASS file with the Apple Jar Launcher program.

Step 3. Update Apple Jar Launcher to the latest version

If, however, after binding Apple Jar Launcher with Java Class Format there were still problems, you should update the program to the latest version.

Step 4. Check for the following problems with the CLASS file

The problem may also be with the file itself if the above steps don't work. This could be due to the file itself, the cleanest issues are:

The affected file may be 0 KB or smaller than expected. Usually this applies to CLASS files downloaded from the Internet in case the download did not finish properly. Downloading the file again should fix the problem.
The computer may have fallen victim to a computer virus or hacker. Perform a virus scan using available and up-to-date anti-virus software. Some antivirus vendors also provide free online scanners. For the best results, we will scan the entire operating system, not just our CLASS file. As a result of the scan, sometimes it is not possible to recover CLASS files, which are deleted if there is a backup of this file, then after restoring it, it must also be scanned.
Older version of CLASS file may not always be supported by the latest software version. On their websites, developers usually offer free solutions to such problems, e.g. in the form of a conversion program or an older version of the program.
The file may be corrupted in a number of ways. Depending on the type of file, it is necessary to repair it accordingly. Sometimes the program itself has options to repair the most popular CLASS file corruption.
The program can also signal the fact of encryption. The encrypted CLASS files can be used by the device on which they were encrypted, on any other device it is required to have the appropriate cryptographic key and decrypt the file before its recovery.
Some of the system directories are excluded from modification. The problem is only writing to the file, not reading it. Copying the CLASS file to another location will fix the problem.
This can happen on a file that does not support multiple access. You may find that another program you are using is preventing you from working with the file. Closing other programs should help. If the error persists after closing other programs, wait for a while. However, some background programs may block the CLASS file while scanning. If nothing helps, please reset the device.