Episode 4. List, Set, Maps, HashCode, Equals and ConcurrentMap! Everything to know about Collections!
In this episode we describe the most used collections in the Java framework, and how can they help you out. We also talk about maps (and the importance of immutable keys), and the equals/hashcode contract (why are these anyways? :). Finally we discuss how to safely access these collections/maps from different threads (and cover the check-then-act operations in maps). If you used a map, or ever got a ConcurrentModificationException, this episode is for you!