Provided are methods, computer programs and apparatus for communication in a distributed object-oriented data processing environment. Requests for retrieval of data items from another data processing apparatus include embedded objects having executable class functions for performing operations at the target data processing apparatus. This has the advantages of the request implicitly sending data as well as requesting data and allows the request to perform a test on data within an object. Objects within the request can be embedded within each other with different encryption and compression applied to the different objects. As well as achieving communication efficiencies, the ability to selectively encrypt components of a request can be used to provide greater security. For example a store may be able to interpret the request, but credit details may be separately encrypted such that only a bank can decrypt that subcomponent of the request.