导出可运行jar后的Java异常

Question

When I try to run the jar, after exporting it using eclipse, this is what I get:

Exception in thread "main" java.lang.UnsupportedClassVersionError: ietstesten : 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)

I don't really know why this happens. I tried importing everything into a new project but it doesn't seem to solve anything.

When I double click the jar I get "Java Exception Occured"

Answer 1

This happens because of your jar file compiled in java 1.8 But you are running in the lower version than 1.8

1. Install Java 8
2. Change compliance level to 1.8 in your IDE

Java Version History

J2SE 8 = 52

J2SE 7 = 51

J2SE 6.0 = 50

J2SE 5.0 = 49

JDK 1.4 = 48

JDK 1.3 = 47

JDK 1.2 = 46

JDK 1.1 = 45

Answer 2

You get the version error when the Jar is compiled with a newer Java version than what you are using to run it with. Did you compile it with Java 8 and are you now running it with Java 7 perhaps?