Walaykum Assalam WaRahmatullah WaBarakatuhu
As a beginner, get yourself updated on java trends and technologies. Learn java from a training institute if you have one locally or learn from many of the free online courses available. This should be your order of learning:
1. Core java - the language and standard libraries, Object Oriented programming
2. Advanced java- threads, jdbc, rmi, the java memory model, garbage collection, etc
3. JavaEE - servlets, jsp, jsf (optional)
4. Spring, Spring MVC
5. Hibernate, NoSQL trends
9. General- Test driven development, continuous integration, domain driven design, Agile, etc.
As you cannot know everything, you should keep yourself updated on the technology even if you do not actually work on it. So, even though your aim would be to be expert in Java, you should look up information on .NET, php, python, etc. This will broaden your knowledge.
Hope this helps.