What are common mistakes developers make with Map?

When working with Maps in Java, developers often make a number of common mistakes that can lead to performance issues or bugs. Here are some of the most prevalent pitfalls:

• Using null keys/values: In HashMap, null can be used as a key or value, but in other types of maps, such as TreeMap, this can cause a NullPointerException.
• Iterating over entries incorrectly: Developers sometimes use an old style for-loop for iteration which can lead to ConcurrentModificationException if the map is modified concurrently.
• Not considering thread safety: When using a Map in a multithreaded environment, failing to use ConcurrentHashMap may lead to inconsistent reads or writes.
• Choosing the wrong Map implementation: Different scenarios may require different types of Maps (e.g., HashMap vs. TreeMap). Selecting the wrong one can affect performance.
• Assuming order: Many developers do not realize that HashMap does not maintain an order of its elements, while LinkedHashMap retains insertion order.