WFC together with the basic Java library provides a powerful set of functions. In those rare cases when Win32 doesn't provide the function you need, the J/Direct Call Builder provides easy access to practically the entire Win32 API. J/Direct also provides access to commercially provided DLLs and to DLLs that you might write yourself.

In this chapter, you've seen how to use the J/Direct Call Builder to access the Win32 API, and you've seen the problems that J/Direct solves. You've also seen a few restrictions on calls to DLL functions that are due to problems J/Direct can't solve.

You've learned how to write your own DLL and how to access it through J/Direct, a technique that provides you access from Visual J Plus Plus code to functions you would rather write in a different language.

Finally, you learned how to use J/Direct to solve a problem that was only partially solved in an app from . J/Direct is a powerful package that extends Visual J Plus Plus into practically every capability the Win32 operating system and many commercial apps provide.

This chapter ends Part II and our discussion of Windows apps. Part II has discussed a number of topics regarding Visual J Plus Plus windowed apps. You've seen how to write generic windowed apps using the Abstract Windowing Toolkit (AWT), how to extend AWT capabilities with WFC, and how to access DLLs directly. The next part of this tutorial will demonstrate a number of new capabilities provided by Visual J Plus Plus v6.