Normally we pack functionality into libraries and use this library to share the functionality. However, during development of several JDeveloper Extensions our goal was to have one shared java source between our JDeveloper 11g and JDeveloper 12c extension.
Off course we wanted the ability to easily develop, test, debug and run the extension, but we also want to share the java code to introduce reusability.
We accomplished this, by creating a separated ‘coresrc’ folder and add this folder as a Java source path both in JDeveloper 11g and JDeveloper 12c. To illustrate two screenshots of the open source project ADF EMG Audit Rules.
A great trick to share your Java source between several projects, where you can still keep project specific source in the regular project src directory.