Java: How to decide between HashMap and TreeMap?

Question

What is the key difference between a HashMap and a TreeMap and what should be the key factor to choose HashMap or a TreeMap?

Answer 1

Because HahsMap gives better performance if you don’t need sorting then go for HashMap otherwise TreeMap would be choice. You have also option available to use LinkdeHashMap which is same fast as HashMap including it gives remove/add/contains functionality and also maintains insertion order.