Cannot start JOSM on OS X 10.10.5

[anonymous]

I am on OS X 10.10.5 and downloaded JOSM here https://josm.openstreetmap.de (Download josm-tested.jar (version 9329)).
I double clicked on the .jar file and got the message that it cannot be opened. I read in the wiki that Java 6 or later is required. I am on Java 8.
I tried from terminal with java -jar josm-tested.jar - no success neither. I get sort of a listing in there...

Then I downloaded JOSM from here https://josm.openstreetmap.de/wiki/De%3ADownload (package.zip for Mac OS X) and double clicked on the Icon which looks like a map. The app seems to start (it appears in the doc) and then it closes down without any warning. I do not even see a window popping up or something.
I turned of Gatekeeper, restarted the computer. Nothing changes.
Any ideas?

[bastiK]

Replying to anonymous:

I read in the wiki that Java 6 or later is required.

Where exactly did you read this? We require Java 7 or later.

I tried from terminal with java -jar josm-tested.jar - no success neither. I get sort of a listing in there...

The terminal output would be crucial information to solve the problem.

[anonymous]

Replying to bastiK:

Replying to anonymous:

I read in the wiki that Java 6 or later is required.

Where exactly did you read this? We require Java 7 or later.

Sorry, Mistyped. Java 7. (https://josm.openstreetmap.de/wiki/InstallNotes#Running)

I tried from terminal with java -jar josm-tested.jar - no success neither. I get sort of a listing in there...

The terminal output would be crucial information to solve the problem.

I get:

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.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$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

[bastiK]

What is the terminal output of java -version?

[anonymous]

Replying to bastiK:

What is the terminal output of java -version?

here:
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-466.1-11M4716)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-466.1, mixed mode)

However: When I go on "Settings - Java - Update" I see
Java 8 Update 66

[bastiK]

Then you either need to uninstall Java 6 or make sure the correct version is selected as default by your operating system.