SOA Suite 12c provides the option to use the Integrated WebLogicServer in JDeveloper as the development run time environment. It comes prepackaged, installs very easily and gets a developer up and running in less than 20-30 minutes. As part of this light(er) weight SOA Suite run time, there is an MDS Repository (file based). Deployment to this run time MDS is done in the usual way. The contents of this MDS instance can be inspected in JDeveloper and resources can be transferred to the local design time MDS instance or exported to a JAR file for further distribution. All you have to do is create a connection to this run time MDS instance.
When you run the EM FMW Control for the Integrated WLS, you can find out about the file system location for the integrated run time MDS. Click on the node Metadata Repositores | mds-soa.
From the drop down menu on top of the right hand side of the page (under mds-soa), select option Target Information.
A popup appears that shows the file system location for the mds-soa instance.
In JDeveloper, open the Resources window. Open the context menu for node IDE Connections | SOA-MDS and select New SOA-MDS Connection.
Provide a name, select File Based MDS as the connection type and specify the directory from the Target information popup as MDS Root Folder.
Test the connection and on success, click on OK.
Even if you have not yet deployed any resources to the run time MDS, you will at least see the soa
You can open resources from the SOA Runtime MDS connection and export from this connection.
Very good blog