This deals with concurrent programming. The wait() and notify() methods are designed to provide a mechanism to allow a thread to be block until a specific condition is met.

However, java.util.concurrent should be used instead of wait() and notify() to reduce complexity.

The wait/notify mechanism in Java is a part of the synchronization features provided by the language to coordinate the activities of multiple threads. It is typically used to manage the communication and synchronization between threads in a multi-threaded environment. The mechanism involves two main methods provided by the Object class: wait() and notify() (as well as notifyAll()).

Here’s a brief explanation of each:

wait(): This method is used by a thread to voluntarily release the lock it holds. When a thread calls wait(), it goes into a waiting state until another thread calls the notify() or notifyAll() method on the same object.
notify(): This method is used to wake up one of the threads that are currently waiting on the object. If multiple threads are waiting, it is not specified which one will be awakened. The awakened thread will compete for the lock before it can continue its execution.
notifyAll(): This method is similar to notify(), but it wakes up all the threads that are currently waiting on the object. This is often used to ensure that all waiting threads get a chance to acquire the lock.

The wait/notify mechanism is commonly used for inter-thread communication and coordination in scenarios where one thread needs to wait for a specific condition to be met before proceeding with its execution.

It’s important to note that the usage of wait(), notify(), and notifyAll() should be done within a synchronized block, as they are designed to work with the intrinsic lock of the object on which they are called. Additionally, these methods should be used cautiously to avoid potential issues such as deadlocks and missed signals.