Here I am listing down most of the important java multithreading interview questions from interview perspective, but you should have good knowledge on java threads to deal with follow up questions. Singleton is one of the most widely used creational design pattern to restrict the object created by applications. If you are using it in a multi-threaded environment, then the thread-safety of the singleton class is very important. In real-world applications, resources like Database connections or Enterprise Information Systems (EIS) are limited and should be used wisely to avoid any resource crunch. To achieve this, we can implement a Singleton design pattern. We can create a wrapper class ... The Object class in java contains three final methods that allows threads to communicate about the lock status of a resource. These methods are wait (), notify () and notifyAll (). So today we will look into wait, notify and notifyAll in java program. wait, notify and notifyAll in Java The current thread which invokes these methods on any object should have the object monitor else it throws java .lang.IllegalMonitorStateException exception. wait Object wait methods has three variance, one ... This article on Synchronization in Java will help you guide your way to learn about synchronizing the multi-threaded programs.