Sec 9: Multithreading Questions
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Multithreading is a process of executing multiple threads simultaneously. Its main advantage is: -Threads share the same address space. -Thread is lightweight. -Cost of communication between process is low.
A thread is a lightweight subprocess.It is a separate path of execution.It is called separate path of execution because each thread runs in a separate stack frame.
Under preemptive scheduling, the highest priority task executes until it enters the waiting or dead states or a higher priority task comes into existence. Under time slicing, a task executes for a predefined slice of time and then reenters the pool of ready tasks. The scheduler then determines which task should execute next, based on priority and other factors.
The join() method waits for a thread to die. In other words, it causes the currently running threads to stop executing until the thread it joins with completes its task.
No, there is no possibility to start a thread twice. If we does, it throws an exception.
yes, but it will not work as a thread rather it will work as a normal object so there will not be context-switching between the threads.
The daemon threads are basically the low priority threads that provides the background support to the user threads. It provides services to the user threads.
No, if you do so, it will throw IllegalThreadStateException
The shutdown hook is basically a thread i.e. invoked implicitely before JVM shuts down. So we can use it perform clean up resource.
We should interrupt a thread if we want to break out the sleep or wait state of a thread.
Synchronization is the capabilility of control the access of multiple threads to any shared resource.It is used: -To prevent thread interference. -To prevent consistency problem.
-Synchronized block is used to lock an object for any shared resource. -Scope of synchronized block is smaller than the method.
Yes. You can lock an object by putting it in a "synchronized" block. The locked object is inaccessible to any thread other than the one that explicitly claimed it.
If you make any static method as synchronized, the lock will be on the class not on object.
The notify() is used to unblock one waiting thread whereas notifyAll() method is used to unblock all the threads in waiting state.
Deadlock is a situation when two threads are waiting on each other to release a resource. Each thread waiting for a resource which is held by the other waiting thread.
