.jar files won't launch Big Sur

Hopefully as a professional java developer I can help you here. First of all if your not developing (compiling) your own java code then all you need is a JRE. As to the version you need - that rather depends on the .jar file you are trying to run. Whoever created it will have used a particular version of Java and you would normally need to run the same or newer version of Java on your machine. Having said that when Java moved from version 1.8 to 11 there were quite a lot of changes and some older java jar files might not work correctly.

Finally - licensing. Oracle took over from Sun when it comes to the ongoing development of Java and for some time they used to provide their java for free. The last version I recall which is free is 1.8 (202) - however don't panic - you can still use any of the open source versions of java.

You can download whichever version you need from here

https://adoptopenjdk.net/releases.html

If your unsure as to the version you need maybe you can let me know where the .jar comes from - hopefully the source of the file might indicate which java version to use. The bulk of .jars still use 1.8 at the moment.

So in summary - if your only running the java application you only need the JRE. If you think you might do some changes and re-compile the code then you are looking for a JDK.

I thought I read somewhere that the original Apple JRE no longer works in Big Sur - I certainly would not use it now as it's too old. Go for one of the downloads in my link above.

If you want to verify the default version of java being used on you machine, open up a command terminal and type

java -version

Hope this helps

Dave

It could be that the java program is expecting to find other files/folders on your hard disk and failing because it cannot find them. Normally when you run the program from the command line it will throw some exception which may indicate the error.

You could copy and paste that so I can see the error.

I suspect this is more of a java question rather than big sur. You can find help here :-

https://coderanch.com/forums

Not all .jar files are intended to run by themselves - they may just provide additional functionality to another java program. Can you let me know where this jar came from - what application it's part of etc?

I see your trying to install something to do with minecraft - I have no experience of that.

As it will be an unsigned application have you tried right clicking on the jar file from finder and then selecting open

You will then need to confirm that you want to open it.

You might find more relevant support on the minecraft forums,

Dave

You could try running from the command prompt.

Open a terminal

cd into the folder where the jar file is located.

type :-

java -jar yourjarfile.jar

If there is any reference in that .jar file that expects the presence of Java 6, then it will not work, or the .jar expects both the Java 8/271 JRE and JDK installed.

If it is not working solely with the JRE, then it may be worth the effort to install the equivalent version JDK as a test. If it then works, or doesn't then you have your answer.

If you run from Terminal as above maybe some addition errors will be displayed in the terminal window.

What happens when you run the command from the terminal ?

The JDK that matches the same version of the currently installed JRE. I am not looking over your shoulder…