With Java-based libraries you can quickly develop a web site, create a game, build a PC program, or even create an application for mobile devices or tablets.
Suppose you need to write a program for microcontrollers or a program for working with large volumes – this will not be a problem for Java. If you want to make a web site, write a Windows application, write a neural network, make a game or write a mobile application, you can do it all using the different libraries and frameworks that are available for this language. Libraries extend the functionality of the language. Once you learn the basic syntax of the language, you can do almost anything you want.