A full stack Java developer is a web developer that uses the Java language in the development of the entire technology stack of a web-based application. The job duties of a full stack Java developer are to create both front-end components, such as user interfaces and back-end components, such as application code and databases. As a full stack Java developer, you must understand how the entire technology stack functions as a whole and have deep expertise of each component. Java is a computer programming language that has become one of the most popular for web application development.