you will need a c compiler or a pascal compiler that makes windows dll library as output. each compiler has it's own syntax to do this.
Or you can create a Windows version of a dll (.NET labels .dll's) but they aren't true .dll's also - Com Objects made from VB are dll's - all it really "represents" is a dynamic link library.
there is one project,& we need to do some changes in that,we need to develop dll or com component i.e. required for that extra functionality ,so that it can be integrated in that project using SDK..how it can be done?
do you mean java sdk? if it is then you will have some problems because of all the things I learned about java the connection with external C code (in this case dll) is very tricky.
Well you must have experience in any of programming languages (capable of producing shared libraries). Best way of doing this is program it in C / C++ language, here is one beginner level tutorial of creating and reusing them explicitely. http://www.apitalk.com/windows-Programming/Create-Dll-Easily-In-C.html Where you can obtain a free IDE Dev C++ to get started with this stuff, from http://bloodshed.net regards