Fix the .jar association program on Windows PC



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  • Latest Version

    Jarfix 3.0.0 LATEST

  • Review by

    Daniel Leblanc

  • Operating System

    Windows XP / XP64 / Vista / Vista64 / Windows 7 / Windows 7 64 / Windows 8 / Windows 8 64 / Windows 10 / Windows 10 64

  • User Rating

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  • Author / Product

    Johann N. Löfflmann / External Link

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If you double-click on a jar file, and your Java application does not start, your .jar association has been hijacked. You can fix the problem with Jarfix.

The root cause of the problem above is, that a program has stolen the .jar association. If you have installed the Java Runtime Environment the first time, the file type called "jar" is assigned to javaw.exe correctly. "jar" is an abbreviation for "java archive" and javaw.exe is the correct program to execute a .jar. However, on Windows, any program can steal a file type at any time even if it is already associated with a Jarfix app.

Many zip/unzip programs prefer to do this because a jar is stored in the .zip format. If you double-click on a .jar, your pack program opens the file, rather than javaw runs the program, because your pack program ignores the meta-information which is also stored in a .jar. In the Oracle bug database there is the low-priority report 4912211 "add mechanism to restore hijacked .jar and .jnlp file extensions", but it has been closed as "Closed, Will Not Fix".

You may also miss the file connection with .jar if you are using a free OpenJDK without an installer. Reinstall the Java Runtime Environment or fix the Windows Registry manually each time this problem occurs.

You can fix this problem very easily with the small but reliable jarfix.exe program. Just double click on it to restore the .jar association with javaw.exe.

What's new in this version:

- from Java 11, Oracle does not provide a dedicated JRE anymore, only a JDK, therefore for x64 and JDK 9+, jarfix 3 will search for a JDK first and then for a JRE, otherwise the latest Java Runtime Environment could not be found if both JDK 11+ and a JRE version < 11 are being installed
- for Oracle JDK < 9 or on 32-bit platforms, the mature search strategy remains unchained
- added option /k in order to search in the Windows Registry only for a JDK and not a JRE
- added support to find a JDK from Azul Systems in the Windows Registry
- added option /z in order to search in the Windows Registry for a JDK from Azul Systems only
- added option /l in order to create a link called "latest" that points to the latest JRE/JDK. The symlink will be stored under the JRE/JDK's parent folder.
- removed option /c, because a more comfortable solution exist: if a <jarfix>.ini file exists, it will be read by the <jarfix>.exe; simply replace <jarfix> with a name of your choice. That way you can call jarfix with different configurations without the need to go to the command line. That feature is also useful for setting up a .jar file association for an OpenJDK bundle that doesn't come with an installer (e. g. the OpenJDK from or
- changed all links from http to https