Running java application fails with "Unsupported major.minor version"

Question

I want to install a java in my linux centos 64bit

when I run it

it gave me an error

what should I install in my server

I have java 1.6

java -jar licence.jar


Exception in thread "main" java.lang.UnsupportedClassVersionError: org/dgt/jl/App : Unsupported major.minor version 51.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:643)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
Could not find the main class: org.dgt.jl.App. Program will exit.

There is a problem with your jar file. You'll need to contact whomever gave it to you. — EEAA, Jan 06 '14 at 19:03

krisFR · Accepted Answer · 2014-01-06T20:46:07.373

Unsupported major.minor version 51.0 means that you have a Java compatibility issue.

In other words, the JAR file has been compiled under a specific JDK, but then you try to run it with an older version of JDK.

51.0 stands for J2SE 7. According to this, here are the major version numbers :

J2SE 7 = 51 (0x33 hex)
J2SE 6.0 = 50 (0x32 hex)
J2SE 5.0 = 49 (0x31 hex)
JDK 1.4 = 48 (0x30 hex)
JDK 1.3 = 47 (0x2F hex)
JDK 1.2 = 46 (0x2E hex)
JDK 1.1 = 45 (0x2D hex)

You should try to run your licence.jar file using Java 1.7

Running java application fails with "Unsupported major.minor version"

1 Answers1