As you look back through the chapters and review these goals, I hope you find that the book has shown that interoperability between .NET and Java today is certainly possible. If you've tried any of the sample code, you might well have seen small adjustments and recommendations that were necessary to get everything working.
I think this is very emblematic of the industry as it is today. Interoperability between .NET and Java is definitely a reality, but now and again small tweaks have to be implemented. As we move toward agreed-upon standards and more mature products, I think we'll all see a dramatic improvement in interoperability.
From a technology perspective, we've covered a lot of areas. There are a few topics that didn't get into the book (such as COM and Java interoperability), but generally we succeeded in covering a broad spectrum of scenarios and challenges.
So, given more time and space, what would have I included? I would have liked to have included a section on how all the different topics presented throughout the book can work together. In many presentations I make, I demonstrate how Microsoft Outlook can connect to a server-side Customer Relationship Management (CRM) system, which is based on J2EE. The CRM server- side application uses a combination of Entity and Session Enterprise JavaBeans (EJBs) for customer records. These EJBs are exposed via Web services by using GLUE, and WS-Security is applied to ensure that only certain records are available to authenticated Web services clients . The Microsoft Outlook client uses a .NET add-in, written in C#, and Microsoft WSE 1.0 to consume the exposed Java Web services. To connect to the CRM system, the user clicks a new contacts folder within his mailbox. This in turn prompts the user for a certificate, which is stored on a smart card. When the user provides a valid certificate, the EJBs are called across the Web services layer, and the records are returned and displayed as new contact items within Outlook.
This type of end-to-end interoperability putting the pieces together that have been presented in this bookhas the potential for creating very compelling solutions. Going back to the duck analogy that was used in the introduction of this book, I tried to show that the user experience is no different than it is when using Microsoft Outlook every day. When users use the add-in, they are typically unaware that the CRM is based on J2EE, how Web services are providing interoperability, or what methods were used to extract the data. Overall, I believe this is a key message to convey .