I will be starting a new project in the near future, that will most likely be a mix of Java and C# technologies. As with many projects recently, the lure of rich user interfaces, that operate well on the Windows platform, has prompted many projects to go with a .Net Presentation layer, and leverage an existing/robust J2EE backend.
Given this new bred of mixed technology development, the use of an Service Oriented Archtecture suites this paradym very well, offer up Web Services ( implemented in J2EE ) to the Gui, and you are off and running. A C# Gui, can be just pointed to the WSDL and the appropriate pumping code will be written for you, and you are blisfully unaware of the fact that the GUI is using a WebService.
The DataSet in .Net rocks, it provides so much functionality for free, that it makes it the prefered data transport mechanism between the presentation layer and the buisiness layer, when dealing with a pure .Net technology stack then DataSet's are the way to go. The question now is how does loved C# class fit into the Mixed technology SOA. J2EE does not have a direct binding to this type, and hence code will need to be wrtitten, if this type is to be incorporated into this environment. Is it worth the effort I ask. ( Comments welcome )
Hibernate is a java framework providing Object Relational Mapping, this is part of the EJB 3.0 specification now, and there is also a .Net version called NHibernate, so is it better to just consider using POJO's and PONO's (Plain Old Java Objects, Plain Old .Net Objects)
Still thinking about this at the moment, so have not come to any conclusion myself, part of my bias towards DataSet's is their flexibility when it comes to binding the data to UI Controls, like the Data Grid, which is the cornerstone of pretty much all User Interfaces these days. But I can also bind Arrays of PONO's to a DataGrid as well, but I loose the relational aspect of the DataSet, that provides me with drill down functionality with minimal of effort.
As mixed technology projects become the norm, rather than the exception, there will be, I hope, a growth in the appropriate glue technology that allows the two technolgies to talk to each other. WebServices is a start, but lacks some of the functionality required to build trading systems, i.e. Realtime data feeds direct to the desktop ( this requires push, not pull ). Janeva is another technology that allows C# objects to talk directly to J2EE objects, this is acheived by providing an alternative Remoting implementation that supports this communication ( worth a look ).
More to come later .....