first you need to learn the Object Oriented Paradigm .and how you can write Classes and objects in java. then try to learn how you can develop desktop applicat

first you need to learn the Object Oriented Paradigm .and how you can write Classes and objects in java. then try to learn how you can develop desktop application you have two main frameworks for the GUI (JavaFX and Swing) I recommend JavaFX because oracle doesn't support anymore Swing. Then comes the best part, the Java Entreprise Edition (JEE ) ,its here where the fun begins ,JEE is for web application s, first you need to learn JSP and Servlet, and then take a look at the web frameworks that exists like (Play, Spring, Struts ,JSF ...)