"Performing action Check Out...[ from oracle.ide.ceditor.CodeEditor ]
Invoking command: [ from oracle.ide.ceditor.CodeEditor ]
Uncaught exception
java.lang.NullPointerException
o.ji.vcs.svn.util.SVNRepositoryInfoValidator.validate(SVNRepositoryInfoValidator.java:58)
o.ji.vcs.svn.nav.ui.ConnectionPanel$ConnectionTesterThread.run(ConnectionPanel.java:412)
Invoking command: [ from oracle.ide.ceditor.CodeEditor ]
Uncaught exception
java.lang.NullPointerException
o.ji.vcs.svn.util.SVNRepositoryInfoValidator.validate(SVNRepositoryInfoValidator.java:58)
o.ji.vcs.svn.nav.ui.ConnectionPanel$ConnectionTesterThread.run(ConnectionPanel.java:412)
The solution is to remove/rename the existing preferences.xml (and possibly the repositories.xml) under the JDeveloper install directory:
%JDEV_HOME%/jdeveloper/system11.1.1.1.33.54.07/o.jdeveloper.subversion
Many Thanks to Nick for help on resolving this issue.