how to write my own programmes using sun java

A small heads-up Charlesase - you need to be more specific when you ask questions on forums. Generally, the more detailed the question you ask the more detailed and useful the answer. A good principle is that if you are going to post a question less than a sentence long, try it in Google first!

So, my general answer to your question - I first learned about PLC's (the night before the interview for my current job) by looking at the "learn PLCs" link at the top of this page. That, plus getting my hands on some hardware to fool with, were what I needed to get started.

- N

writing of software programmes

I am talking of writing of programmes,like writing a chemical software,computer software programme using C++.

Well, I am afraid the answer to that is http://www.somewhereelse.com/

Download Dev-C++ http://www.bloodshed.net/devcpp.html (it's free) and write yourself a few "hello world" type programs (http://www.cplusplus.com/doc/tutorial/tut1-1.html).

http://www.techtutorials.net/Programming/Java/

lots of tutorials for a little bit of everything here.
www.techtutorials.net