A Java developer designs, develops, and manages Java-based applications. They analyze user requirements, determine application functionality and usability, and code software to meet those needs. They often work with software developers and web designers to integrate Java into business applications, software, and websites. They also debug and resolve technical issues, improve application efficiency, and conduct software analysis, programming, and testing. Furthermore, they update existing Java applications, regularly review and recommend changes to improve established java application processes, and often use tools like Oracle and SQL databases, Java Server Pages (JSP), and Enterprise Java Beans (EJB).