Testing JSR-160 Runtime ... failed

Sometimes when we configure Jdeveloper for first time to some server, we get  below error:

Testing JSR-160 Runtime ... failed.
Cannot establish connection.
Testing JSR-160 DomainRuntime ... skipped.
Testing JSR-88 ... skipped.
Testing JSR-88-LOCAL ... skipped.
Testing JNDI ... skipped.
Testing JSR-160 Edit ... skipped.
Testing HTTP ... success.
Testing Server MBeans Model ... skipped.

One solution  which you will find everywhere over internet is to remove any proxy in Jdeveloper, or have the same proxy as in browser:
Goto Tools -> Preferences in jdeveloper and type "proxy" in the search box, the proxy setting will appear. Uncheck the proxy checkbox , save the setting and restart Jdeveloper.

However in some cases this is not the issue, if above does not work do below:
update your host file and add:

Adminserver-IP   Hostname

now test your connection, your test should be successful. 
Let me know how it goes :)