Java J2ee Planet

Java concurrency model uses locks to implement mutually exclusive access to objects in a multi-threaded environment and locks are associated with every object in Java (of type 'Object'), not only with Threads. wait, notify/notifyAll methods are used by threads to communicate with each other while trying to access a common object. Putting it differently, objects become a medium via which threads communicate with each other. For example: suppose there is a 'telephone' object, which at one point of time can be used by only one thread. Like every other object in Java, 'telephone' object would also have an intrinsic lock (monitor) associated with it which at one point of time can be acquired by only one thread. Suppose the 'telephone' object requires activation before it can be used and suppose only a few admin threads can activate the 'telephone' object.

What are three ways in which a thread can enter the waiting state? Or What are different ways in which a thread can enter the waiting state? A thread can enter the waiting state by the following ways: 1. Invoking its sleep() method, 2. By blocking on I/O 3. By unsuccessfully attempting to acquire an object's lock 4. By invoking an object's wait() method. 5. It can also enter the waiting state by invoking its (deprecated) suspend() method. What is the difference between yielding and sleeping? When a task invokes its yield() method, it returns to the ready state, either from waiting, running or after its creation. When a task invokes its sleep() method, it returns to the waiting state from a running state. How to create multithreaded program? Explain different ways of using thread? When a thread is created and started, what is its initial state? Or Extending Thread class or implementing Runnable Interface. Which is better? You have two ways to do so. First, making you...