It is a bad practice to use Sun's proprietary Java classes?

Question

The compiler display warnings if you use Sun\'s proprietary Java classes. I\'m of the opinion that it\'s generally a bad idea to use these classes. I read this somewhere. Ho

Answer 1

Because they are internal APIs: they are subject to change in a undocumented or unsupported way and they are bound to a specific JRE/JDK (Sun in your case), limiting portability of your programs.

Try to avoid uses of such APIs, always prefer a public documented and specified class.