Skills that a Java Developer should possess are the following :
1.Java 8 new Features - Lambda Expressions, Streams API,Functional interfaces.
2.Good command on IDE for JAVA ( EclipseIDE, IntelliJ IDE etc)
3.Collection API
4.Spring Framework
5.Hibernate Framework
6.Any Database,(Mysql, NoSql)
7.Hands-On command on multithreading & exceptional handling.
8. Servlets/JSP