Papyrus class diagram has been able to generate Java code by adding "Papyrus profile for Java Models", "Papyrus Java Classes Generator" and "Papyrus Reverse". In The new Papyrus 2.0.0 there are no packages like above. So how do I add the "Java registered profile" to the profiles list so I can generate Java code from my UML Class diagram?
You need to add the "Designer-JAVA" additional component in order to get this functionality. On the Papyrus toolbar, you should see the Papyrus icon (there are actually two - yes, it can be confusing...). Click on the one that shows the "Install Papyrus Additional Components" tool tip. In the "Modeler Extensions" section, select the "Designer-JAVA" component and install it. This will download and install the profile, library, and code generation components. You will then be able to apply both the Papyrus Java and the Papyrus Code Generation profiles.
Added: Note that you can also go through "Help"> "Install Papyrus Additional Components" to install additional components.