Java Wait, Notify, and NotifyAll: Understanding the Differences and Avoiding Deadlocks

source: javarevisited.blogspot.com

Have you ever worked with multiple threads in Java and wondered about the best ways to make them talk to each other? Java gives us some handy tools for this — wait(), notify(), and notifyAll(). But using them the wrong way can cause big problems like deadlocks where your program gets stuck.

In this article, we’ll look at:

• What these methods do and how they work
• The key differences between them
• When to use each one
• A real scenario where using notify() instead of notifyAll() can cause problems
• How to avoid these problems

Understanding Thread Communication Basics

Before we dive into the details, let’s understand why we need these methods. When we have multiple threads running at the same time, they often need to work together. For example:

• One thread might produce data that another thread needs to use
• A thread might need to wait for a certain condition before it can continue
• Multiple threads might need to take turns using a shared resource