Question

I am currently experiencing a problem in my RCP application and wanted to ask, if someone stumbled over the same problem and can give me some valuable hints:

My RCP application allows plugins to provide implementations of a specific abstract class of my model (singleton) to extend my model during runtime via the update manager. I instantiate these classes via

    extensionPointImplementation.createExecutableExtension(..) 

after parsing the Eclipse registry. I can serialize the created instances using the default Java serialization API.

Now to the problem: The plugin trying to deserialize the objects cannot find the class implementations of the model extensions due to the fact, that there is no plugin dependency between the plugins. Nevertheless, it is not possible for me to create such a dependency which would make the idea of extending the model during runtime obsolete.

Is it possible to solve this problem by using the default Java serialization API or do I have to implement my own serialization (which parses the Eclipse registry and creates the instances via the line shown above if all necessary plugins are available, otherwise throw an exception) which might be based on the default Java serialization API (if possible I do not want to create the serialization completely by myself)?

Thanks.

Answer 1

You need to define a so called buddy policy.
In the bundle trying to instantiate the class add

Eclipse-BuddyPolicy: registered

to the manifest.mf.
In the bundle providing the class add

Eclipse-RegisterBuddy: <symbolic name of the bundle instantiating the class>

to the manifest.mf.