Java Pitfalls - Nulls and NullPointerException
Pitfall - Making good unexpected nulls
Pitfall - Using null to represent an empty array or collection
Pitfall - Returning null instead of throwing an exception
Pitfall - Not checking if an IO stream isnt even initialized when closing it
Pitfall - Using Yoda notation to avoid NullPointerException
Pitfall - Unnecessary use of Primitive Wrappers can lead to NullPointerExceptions