How do I use ConcurrentHashMap in Java?

How do I use ConcurrentHashMap in Java?

ConcurrentHashMap is a thread-safe variant of HashMap. You can use it to store key-value pairs in a concurrent environment.

Can you show me a simple example of how to add and retrieve elements?

Sure! Here's a quick example:

ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
map.put("key1", 1);
Integer value = map.get("key1");
System.out.println(value); // Outputs: 1

What happens if two threads try to update the same key?

ConcurrentHashMap handles concurrent updates by allowing multiple threads to read and write without locking the entire map, ensuring thread safety.

Are there any performance considerations I should be aware of?

Yes, while ConcurrentHashMap is efficient for concurrent access, excessive contention can lead to performance degradation. It's best to minimize contention by using appropriate data structures.