This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
In my project, I have a java application and a dot net application. The dot net application and the java application communicate to the database. How do I connect the dot net application and java application?
While Bill is totally right (you can use web services, sockets, flat files, XML, JSON...) one approach I've used is JNative (A JNI opensource API). It's likely that one of the other methods is better for you, but if you can turn your Dot Net app to a DLL and access it in Java, there's another option for connecting the two for you...
That completely depends on the .Net application. But before you decide on a course of action I still think you need to clarify what you mean by "connecting" the two applications. If you're having trouble putting that into words, perhaps you could give an example of what could be done with this "connection". Or an example of something that might happen if you had it. Try to make those examples as detailed as possible.