Java Multithreading: Creation Methods, Lifecycle, Communication, Thread Pools, Locks, and Concurrent Containers

Four Ways to Create Threads in Java

Java provides four primary ways to create a thread: extending the Thread class, implementing the Runnable interface, implementing the Callable interface, and using a thread pool.

Java Thread Lifecycle

The lifecycle consists of five states: creation (new), ready (runnable), running, blocked, and terminated (dead).

Thread Communication and Cooperation

Threads transition between states using methods such as start(), sleep(), wait(), join(), run(), notify(), and notifyAll(), enabling coordination and data exchange.

Thread Pool

A thread pool manages a reusable set of worker threads, reducing thread‑creation overhead and improving resource utilization for concurrent tasks.

Thread Locks

Common Java synchronization mechanisms include synchronized, ReentrantLock, Semaphore, and AtomicInteger, each offering different performance characteristics and usage scenarios.

Concurrent Containers

Java provides several thread‑safe collection classes such as ConcurrentHashMap, ConcurrentQueue, BlockingQueue, and CopyOnWriteArrayList, which simplify concurrent data access and manipulation.