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.defineClass(ClassLoader.java:621)    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)    at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)    at java.net.URLClassLoader.access$000(URLClassLoader.java:56)    at java.net.URLClassLoader$1.run(URLClassLoader.java:195)    at java.security.AccessController.doPrivileged(Native Method)    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)    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)    at org.codehaus.classworlds.Launcher.main(Launcher.java:47)