Oracle MDS File Does not Exist

Sometimes, after you import a project to your JDeveloper, if that project refers to files in MDS, and complains that the reference files are not available, but if you check in the MDS, the files are actually there.

So usually this is due the MDS that the project refers to does not have the required files. Therefore

1) you either need to put the files in the default MDS referenced by the project, OR
2) you need to make the project to refer to the correct MDS that has all the necessary files. 

For second option, this is what you need to do:

1) Edit adf-config.xml. Make sure yours looks like something like below

2) Restart your JDeveloper.

3) If things did not change, close the Application, then restart your JDev, then reimport that project.