Can't We All Just Interoperate?

So I'm trying to write a program to manipulate the Tablet PC Input Panel from within a Java application. So I have to use JNI to interop with a native .DLL written in C++. My DLL uses Win32 to find the handles to the Java application edit windows and then uses COM to manipulate the TIP. I dunno': I feel like throwing some gcroot\<String \^>s in there, just to cover all bases.