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I need some help. This is the first time I am trying to create a JAR file for a project I made in IntelliJ. It is for school, and the deadline is very soon and I need to submit a working JAR file. I have looked but can't find a solution. The error I get in CMD when trying to run the JAR is below:

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: Main has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

I understand it has something to do with versions of the JRE but I can't fix it. I'm using IntelliJ. The JAR needs to be able to run on my lecturers computer so I'm worried even if it works for me on my PC, it won't work for him. Any advice will be appreciated

Botje
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Alex Smith
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  • Change the target language level to the lowest possible, see https://stackoverflow.com/a/12900859/104891 for the relevant configuration screenshots. – CrazyCoder Jan 10 '20 at 02:38
  • You could ask the instructor what java version they will be using. https://stackoverflow.com/questions/9170832/list-of-java-class-file-format-major-version-numbers Yours shows version 55 which is good, but 52 is reasonable. If the prof is supporting java 11, then you should be ok as is. Try using a java 11 jre for running the jar. If they're using java 8, then you need to set the target level to java 8. – matt Jan 10 '20 at 09:03

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