These days PHP and .NET are popular in our region for development of web based applications. JAVA is very much popular but it is used for large scale applications mostly.
Aim of CS506 is to teach you web programming once you have learnt all the concept of web programming; you will be able to learn languages like PHP or .NET very easily.
JAVA is very rich because it is found every where if you have good command over java you can either go to Mobile , Desktop or Web programming.