The most reliable way to fix Java problems is usually to reinstall Java on your computer, although there are also many other methods and tools available for repairing Java. Access the Control Panel through the Start menu located at the bottom-left of your screen. Double-click on "Add/Remove Programs."

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.

Some developers prefer to reinstall the Java Runtime Environment or fix the Windows Registry manually each time this problem occurs. A much simpler solution, however, is to use Jarfix to repair these faulty .jar files and re-associate them with the Java Runtime Environment. This lets you run your Java files and execute your JavaScript as expected.

Contact the website or application developer to notify them of the issue. Sometimes a corrupted file in the Java cache can prevent an application from running. You can safely delete the temporary files that Java downloads since Java will download them again and ensure they are up-to-date.