When I first stared with Java programming, the fist program I wrote was HelloWorld in Java. That time I just copied it from a text book we are referring, I didn't know anything about it. It took me lot of time to understand everything about Helloworld in Java and how it work. From that time, I make it a rule to start with Helloworld with any new programming language I learn and try to understand every single element of it in as much as detail as possible but to be frank its not easy. When you write Helloworld you are not capable to understand everything about it and I found it better that instead of learning everything in one go, you should give yourself some time to let the knowledge you learned sink in. It's even better if you write Helloworld multiple times without looking at  the book. I have found that doing it repeatedly helps you to understand it better. So, why after so long years I decided to write about Helloworld program in Java and what is meaning of different components of it? Well, one of my reader who is starting with Java asked me this question to write about it and I realize that since many beginners also visit my blog, its fair to them to write tutorials which explains basics right from Helloworld in Java.