What collections exist in Java or other programming languages that ensure safety when working with multiple threads?

In Java and C#, there are collections that ensure safety when working with multiple threads:

In Java:

• ConcurrentHashMap — thread-safe implementation of a hash table.
• CopyOnWriteArrayList — thread-safe list, optimal for scenarios with many reads and infrequent modifications.
• BlockingQueue (e.g., LinkedBlockingQueue) — thread-safe queue with blocking operations.
• Collections.synchronizedList/Map/Set — wrappers for synchronizing regular collections.

In C# (.NET):

• ConcurrentDictionary<TKey, TValue> — thread-safe dictionary.
• ConcurrentQueue<T>, ConcurrentStack<T>, ConcurrentBag<T> — thread-safe collections for different scenarios.
• BlockingCollection<T> — wrapper over thread-safe collections with support for blocking operations.

Using these collections helps avoid race conditions and ensures correct operation in a multithreaded environment.