Creating a reliable and secure application is much easier if you pack the code into neat blocks. The module system in Java is the locale for creating such blocks. You can now monitor the interactions of different JARs and easily detect missing dependencies. Fundamental architecture changes have affected the Java kernel since version 9. All kernel APIs are distributed as modules, and for libraries, frameworks and applications, a similar approach can be considered good practice and recommendation. You will learn best practices for modular design, application debugging, and deployment before going into production.