You won't be able to view the class files from Jdeveloper , you need to decompile to convert them back to
java file . All your java files should be in Myprojects and class files should be Myclasses . (Only java files are editable not class files )
Make sure you create OA project and OA work space , now select your project and import the java file it should allow
you to edit and compile from Jdeveloper .
But for the simplicity if you want to decompile the class file in the Jdeveloper you will have to add any decompiler in your Jdeveloper via External Tools Option.
Now You will be able to see all the contents of the class file in the same place.