I want to run a jar file in Linux (CentOS, 32-bit). But the following error occurs. What is the reason?[root@server ~]# java -jar keygen.jarException 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 exiMy Java version:java version 1.6.0_24OpenJDK Runtime Environment (IcedTea6 1.11.14) (rhel-1.42.1.11.14.el5_10-i386)OpenJDK Client VM (build 20.0-b12, mixed mode)
Java fails with Could not find the main class
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