Nothing wrong with your environment, there really is no entry point to your project. The main method in the screenshot does not have the String[] args parameter. This is not C/C#/C++. You have to specify the String[] args no matter if you use them or not.
The signature of the main method is shown below:
Also, the following link may be beneficial for you:
http://download.oracle.com/javase/tutorial/getStarted/application/index.html