What are the different types of concurrent collections in Java?

What are the different types of concurrent collections in Java?

In Java, concurrent collections are designed for use in multi-threaded environments. The main types include:

1. ConcurrentHashMap - A thread-safe variant of HashMap.
2. CopyOnWriteArrayList - A thread-safe variant of ArrayList that copies the entire array on each write.
3. BlockingQueue - An interface for thread-safe queues that support operations that wait for the queue to become non-empty when retrieving elements.
4. ConcurrentSkipListMap - A scalable concurrent NavigableMap implementation.
5. ConcurrentLinkedQueue - A thread-safe queue based on linked nodes. Would you like to know more about any specific type?

Can you explain how ConcurrentHashMap works?

Sure! ConcurrentHashMap allows concurrent access by dividing the map into segments. Each segment can be locked independently, allowing multiple threads to read and write without blocking each other. This improves performance in multi-threaded applications. Would you like to see an example of its usage?

Yes, please provide an example.

Here's a simple example:

ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
map.put("A", 1);
map.put("B", 2);

// Using a lambda expression to iterate through the map
map.forEach((key, value) -> {
    System.out.println(key + " : " + value);
});

This code initializes a ConcurrentHashMap and iterates through its entries. Let me know if you have more questions!