The following are the skills required for a Java Developer:
Java-based web services
Relational database, ORM & SQL
J2EE framework
Object-oriented design & analysis
JSP
Enterprise Java Beans (EJB)
ESL, X query, XML
Test-driven development
If you want to become a Java Developer, check out this Java Course by Intellipaat.
Also, watch this video to know the skills required for a Java developer: