What are the best practices for using HashMap in Java?

What are the best practices for using HashMap in Java?

Some best practices include using the initial capacity and load factor wisely, avoiding null keys, and using immutable objects as keys.

Why should I avoid null keys in HashMap?

Using null keys can lead to unexpected behavior and make your code harder to debug, as it can cause NullPointerExceptions.

What is the difference between HashMap and Hashtable?

HashMap is not synchronized and allows null keys, while Hashtable is synchronized and does not allow null keys.

Can you give an example of how to initialize a HashMap?

Sure! You can initialize a HashMap like this: HashMap<String, Integer> map = new HashMap<>(initialCapacity, loadFactor);.