title: Java 6 Unsupported major.minor version 51.0
body: <p>I recently uninstalled Java 8, to use Java 6 as I want my code/creations to be usable by more people than just those on Java 8. When I do <code>mvn - version</code> it returns:</p>
  
  <pre><code>Exception in thread "main" java.lang.UnsupportedClassVersionError: org/apache/maven/cli/MavenCli : Unsupported major.minor version 51.0
      at java.lang.ClassLoader.defineClass1(Native Method)
      at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
      at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
      at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
      at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
      at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
      at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:401)
      at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
      at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271)
      at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:254)
      at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
      at org.codehaus.plexus.classworlds.launcher.Launcher.getMainClass(Launcher.java:144)
      at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:266)
      at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
      at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
      at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
  </code></pre>
  
  <p>When I do <code>java -version</code>:</p>
  
  <pre><code>java version "1.6.0_45"
  Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
  Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)
  </code></pre>
  
  <p>Everything seems fine with Java, but this also happens when I try to run executable JARs. I got around it by manually doing java -jar (jar name)</p>