current josm won't start on ubuntu-linux

[akvds@…]

Hi there,

i just installed josm, but could launch it.
So here's the crash-log when i start josm from the command-line:
Using /usr/lib/jvm/java-6-openjdk/bin/java to execute josm.
Exception in thread "main" java.lang.UnsupportedClassVersionError: JOSM : 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: JOSM. Program will exit.
christian@christian-Laptop:~$ java -version
java version "1.6.0_31"
OpenJDK Runtime Environment (IcedTea6 1.13.3) (6b31-1.13.3-1ubuntu1~0.12.04.2)
OpenJDK Server VM (build 23.25-b01, mixed mode)

If you know any solution, please let me know, otherwise i'll wait for the next release.

Kind regards

Christian

[akks]

Sorry, newer JOSM will not work on Java 6. We migrated to Java 7. https://josm.openstreetmap.de/ticket/8465
It is a bug in repository if you get new version with openjdk-6.

Try sudo apt-get install openjdk-7-jre and the problems should vanish.

[JamesZD]

If that did not fix it for you it might be because you have both Java 6 and Java 7 installed and it is defaulting to 6. ​http://askubuntu.com/questions/272187/setting-jdk-7-as-default explains how to fix this using

sudo update-alternatives --config java

and selecting the appropriate version. I hope that helps.