What is .jws , .jpr and .jpx files in jdeveloper/adf?
The .jpx file contains configuration information that JDeveloper uses in the design time to allow you to create the data model project with ADF Business Components. It also contains metadata that defines how a shared application module is used at runtime. Because the shared application module can be accessed by any data model project in the same Fusion web application, JDeveloper maintains the scope of the shared application module in the ADF Business Components project configuration file.
http://docs.oracle.com/cd/E15586_01/web.1111/b31974/appendixa.htm
Another blog I found for easy understanding
When you create an application in Jdeveloper with “JSF , ADF BC” as template, two project gets created “Model” and “ViewController”. And a file
1) .jws which is used for storing the projects added in the workspace(check your workspace on disk).
Under the Model and ViewController projects two files gets created as “Model.jpr” and “ViewController.jpr”.
2) .jpr file is used to store the project related information like java files created in the project etc.
Once you start creating the Entity or View object under the Model, one more file gets created under the Model/src/Model.jpx.
3) Model.jpx file contains all the application modules defined in your Model project. And other configuration details such as database connection used in model layer. Some times during development, if you get “JBO 30003” or database error, then check the “_NamedConnection” parameter in the same file, if it is pointing to the correct database connection name. Entity object is the Java object representation of the database table row from which it is created. Once your create an Entity object(say EmpEO), two files which gets created.