CODEWITHSUNDEEP
javajarclient
Ramin Amiri
Ramin Amiri

Reputation: 161

"A java exception has occurred" when opening .jar

I've made a client for my game and I wanted to jar it, I used jarmaker and did I'm sure I did everything correctly, but when I try to open the .jar file, it says "A java exception has occurred" any help is appreciated.

Exception in thread "main" java.lang.UnsupportedClassVersionError: client : Unsupported major.minor version 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)

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Upvotes: 3

Views: 267228

Answers (4)

Mithun Theertha
Mithun Theertha

Reputation: 181

This error usually happens when compiled in higher JDK version and ran in the lower version of JDK and if your code has some features present in the higher versions. Usually this happens because by default in the OS if java -version is searched it might show some old JDK version, so either change global env variable's value if you have privileges to do so else e.g., in linux instead of typing only 'java' while executing, type the complete path e.g., /usr/jav/jdk1.8/bin/java <<.class||.jar>>. This will resolve the issue.

Upvotes: 2

Omore
Omore

Reputation: 620

I generate JAR file in NetBeans once I double click on JAR file I got an error

A Java Exception has occurred.

I just create new folder put JAR file inside that folder and also place lib folder that is used for Java project and finally JAR file is working fine.

Upvotes: 2

Joshi
Joshi

Reputation: 631

Upgrade the jdk version. You can upgrade it by uninstalling the older version from control panel and installing newer version of jdk. Get the new version here http://www.oracle.com/technetwork/java/javase/downloads/index.html

Upvotes: 2

StephaneM
StephaneM

Reputation: 4899

You compiled your jar with a JDK version superior to the JDK used to launch the jar file (you might have compiled with 1.7 and try to run it with 1.6).

2 solutions:

  • If you don't use specific features of the JDK you use to compile, set its target to the previous version (in the above example add the flag -target 1.6 to you compiler options)
  • Upgrade the JDK used on the client.

Upvotes: 10

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