[Solved] Java JDK Ubuntu

ardianta@imajinasi:~/Code/java$ java Coba
Exception in thread "main" java.lang.UnsupportedClassVersionError: Coba : 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: Coba. Program will exit.
ardianta@imajinasi:~/Code/java$ nano Coba.java
ardianta@imajinasi:~/Code/java$ java -version
java version "1.6.0_30"
OpenJDK Runtime Environment (IcedTea6 1.13.1) (6b30-1.13.1-1ubuntu2~0.12.04.3)
OpenJDK Client VM (build 23.25-b01, mixed mode, sharing)
ardianta@imajinasi:~/Code/java$ sudo update-alternatives --config java
[sudo] password for ardianta:
There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                           Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-6-openjdk-i386/jre/bin/java   1061      auto mode
  1            /usr/lib/jvm/java-6-openjdk-i386/jre/bin/java   1061      manual mode
  2            /usr/lib/jvm/java-7-openjdk-i386/jre/bin/java   1051      manual mode

Press enter to keep the current choice[*], or type selection number: 2
update-alternatives: using /usr/lib/jvm/java-7-openjdk-i386/jre/bin/java to provide /usr/bin/java (java) in manual mode.
ardianta@imajinasi:~/Code/java$ java Coba
Ini adalah program java
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
    at Coba.main(Coba.java:6)
ardianta@imajinasi:~/Code/java$ sudo update-alternatives --config java
There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                           Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-6-openjdk-i386/jre/bin/java   1061      auto mode
  1            /usr/lib/jvm/java-6-openjdk-i386/jre/bin/java   1061      manual mode
* 2            /usr/lib/jvm/java-7-openjdk-i386/jre/bin/java   1051      manual mode

Press enter to keep the current choice[*], or type selection number: 2
ardianta@imajinasi:~/Code/java$ $JAVA_HOME
ardianta@imajinasi:~/Code/java$ $java
ardianta@imajinasi:~/Code/java$ $java_home
ardianta@imajinasi:~/Code/java$ neno Coba.java
No command 'neno' found, did you mean:
 Command 'nano' from package 'nano' (main)
 Command 'neso' from package 'tryton-neso' (universe)
 Command 'xeno' from package 'xenomai-runtime' (universe)
 Command 'neko' from package 'neko' (universe)
 Command 'nero' from package 'alliance' (universe)
neno: command not found
ardianta@imajinasi:~/Code/java$ nano Coba.java
ardianta@imajinasi:~/Code/java$ javac Coba.java
ardianta@imajinasi:~/Code/java$ java Coba
Ini adalah program java
ardianta@imajinasi:~/Code/java$ java -version
java version "1.7.0_65"
OpenJDK Runtime Environment (IcedTea 2.5.1) (7u65-2.5.1-4ubuntu1~0.12.04.2)
OpenJDK Client VM (build 24.65-b04, mixed mode, sharing)
ardianta@imajinasi:~/Code/java$



referensi: http://stackoverflow.com/questions/7237536/exception-in-thread-main-java-lang-unsupportedclassversionerror-a-unsupporte