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Read the API doc and FAQ for the IDE to see how it works.

Does it use the javac command to do a compile?

Do you compile them on that computer? What command does the compilation?

If you have the JDK installed, the jar command file is in the same folder as the javac command

If you don't have a JDK installed, you won't have the jar command.

It should be in the JDK folders, not the jre

Find where the JDK is installed and use the OS's search function to find the jar command.

That looks like a message from the OS saying it can not find the jar command. Windows uses the contents of the PATH environment variable to find commands. If the folder with the jar command is not...