Explain Java ConcurrentHashMap and queues

During an interview, you are asked conceptual questions about Java's concurrency primitives. Provide a detailed explanation of:

1. How Java's ConcurrentHashMap is structured internally, how it delivers thread-safe access, and how it attains high concurrency. Compare it against HashMap and Collections.synchronizedMap.
2. How Java's concurrent queue implementations (for instance ConcurrentLinkedQueue, LinkedBlockingQueue, and ArrayBlockingQueue) operate internally, and how they offer thread safety plus, when applicable, blocking behavior. Describe the underlying data structures, locking or lock-free approaches, and typical use cases for each. Overview: This question assesses a candidate's knowledge of Java concurrency primitives and concurrent collection implementations, centering on thread safety, synchronization mechanisms, lock-free techniques, and blocking versus non-blocking queue behavior.