When moving to Java with a team with little Java experience, it is important to make sure the students know Java. One way that I learned Java and have taught new members Java is through Stanford's CS 106A introductory programming course(Link Below). This course helps teach students Java and also how to solve problems using programming. After students have learned how to use Java it is also useful to read other teams robotics code on github. I learned a lot about programming robots from reading 254's code on github.
Stanford CS 106A
Team 254 Github