What is Jarfix? Can I trust Jarfix?

Most of us have already jarred up our Java applications once or twice. Jarfix tries to make the process less cumbersome by writing the jar timestamp right back where it belongs. It works with both jar and war files, regardless of OS.

Some people will say jar fix doesn’t work, but that’s only because they tried to jar up a jar that already had a timestamp on it. Jarfix can handle that too. It will always jar up the correct file and write the right time back onto it.

Some people like to answer: “Yes, I know jarfix exists and I use jarfix download. Jarfix is an extra tool that I don’t need.”

Its true jar fix won’t help you with that, but has it ever occurred to you that people answer this way because they’re tired of having timestamps forced on them by other tools? jarfix will never force timestamps onto files. Jarfix only reads jar archives and writes a new jar with the correct timestamp on it.

There’s also a similar tool that never has been updated for 7 years, jarfix4jrt. Jarfix does everything jarfix4jrt can do. jarfix is not jarfix4jrt , jarfix is newer and better! If I ever get jarfix4jrt to work on Java 9, jarfix will probably become jarfix2jrt and jarfix4jrt will just die.

• For those of you running jarfix on UNIX: jarfix is compatible to javac. Jarfix works fine with Solaris 10 and 11, but it fails with very mysterious errors under FreeBSD. jarfix has been successfully tested with OpenJDK and IBM JDK, both 32bit and 64bit on Debian GNU/Linux and FreeBSD. Jarfix uses GNU utils such as sha1sum or jar. Jarfix will not touch Windows executables!
• To be fair: Jarfix might fail when jar fixing a jar file that jarfix jarred up at some point. Jarfix will not break your jar: It will just leave it as it is if this happens and report an error.
• WARNING: Jarfix can’t fix jar files created by Java 1.7 or newer! jarfix uses the old version of jar (called ’98’). You can use jarfix to jar up your jar files of course, but the jar timestamp will be fixed after jar gets updated. If you want to run jar fixed jar files on Java 1.7 or newer, you’ll have to change the filing date of your jar by hand.

As far as I know, class 9 and 10 bytes are never used in any jar format. Jarfix will never tamper with jar class files, so you can use jarfix to jar jar archives created by Java 1.3 or newer at any time!

Can I trust Jarfix?

Sometimes Jarfix can help you, especially if the problem is not caused by Java Runtime but rather some other application interfering with or modifying your installation. Jarfix provides several ways to work around problems that may occur because of damage to virtual machine (VM) dynamic libraries. Jarfix repairs known bugs in java jarsigner, javac, jar, java task force, java functional test, java rink, jar cleaner, and almost all other VM image/directory files. Jarfix is tried and tested by several users with different problems and thus considered stable for this purpose.

For most end-users Jarfix can be run without any detailed knowledge or expertise in the area of virtual machines and their operation.

Jarfix is a tool that tries to solve problems in Java installations. It should only be used when the solution cannot be solved by other means. If you can solve your problem another way, it is preferred to do this instead of using Jarfix. The author provides no guarantees and does not take responsibility for any damage caused while running Jarfix.

Jarfix is very simple to use. It can be run from the command line by passing it an optional parameter that describes the problem you are experiencing, for example, jarfix -jvm . Jarfix will try all applicable solutions until one of them succeeds or it cannot continue trying. When this happens, an output screen should be displayed that describes the solution that was used. If the problem persists after running Jarfix, please try one of the other solutions on this site.

If you have a problem with jarsigner or javac not being able to find you. keystore file on Windows 95/98/Me, turn off ‘hide protected operating system files in the Windows Explorer Folder options.

If Jarfix cannot find a solution, you can try to use the problem description to solve the problem yourself by finding out which jar/directory files are used by other applications or services and removing them from those locations. If this doesn’t work you will have to contact the vendor of those products for support or search the internet for other help.