Maven Unsupported major.minor version 51.0

If you are getting the below error message while working on Maven then make sure that theJAVA_HOME environment variable has been set correctly.

bash-3.2$ mvn --versionException 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:637)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
	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)

bash-3.2$

Note this is for Mac OS X running 10.10 Yosemite with JRE version 1.8

1. Open Terminal,

2. Run Command : echo $JAVA_HOME

3. Check if the jre path set is correct : /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home/

4. If not then use the following command to set it : export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home/

5. Now to verify if the issue is resolved run command : mvn --version

   bash-3.2$ mvn --version
   
   Apache Maven 3.3.3 (7994120775791599e205a5524ec3e0dfe41d4a06; 2015-04-22T17:27:37+05:30)
   Maven home: /Users/rakeshswami/Setups/apache-maven-3.3.3
   Java version: 1.8.0_25, vendor: Oracle Corporation
   Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home/jre
   Default locale: en_US, platform encoding: UTF-8
   OS name: "mac os x", version: "10.10.3", arch: "x86_64", family: "mac"
   
   bash-3.2$

6. If everything worked fine you should get no error and get an output as above.