Q) What threads will start when
you start the java program?
A) Finalizer, Main, Reference Handler, Signal dispatcher.
Q) Thread
Thread is a smallest unit of dispatchable code.
A)
Thread is a smallest unit of dispatchable code, Process is a sub program will
perform some specific actions.
(I) Process is a heavy weight task and is
more cost. (ii) Thread is a lightweight task, which is of low cost.
(iii) A Program can contain more than one thread. (v) A program under execution is called as process.
Q) Sleep(), wait(), notify(), notifyAll(),
stop(), suspend(), resume()
wait - wait for a thread until some specific
condition occurs (Or) Tells the calling thread to give up the monitor and go to sleep until
some other thread enters the same monitor and calls notify().
notify( ) - wakes up the first thread that called wait() on the same
object.
notifyAll( )- wakes up all the threads that called wait() on the same
object, the highest priority thread will run first.
stop( ) - The thread move to dead state.
suspend( ) & resume( ) - To pass and restart the execution of a thread. In case of
suspend, thread will be suspended by calling the lock on the object. Resume
will restart from where it is suspended.
join( ) - wait for a thread to terminate.
Yield
method temporarily stop the callers thread and put at the end of queue to wait
for another turn to be executed. It is used to make other threads of the same
priority have the chance to run.
- Thread.sleep(milliseconds, nanoseconds);
Multithreading is
the mechanism in which more than one thread run independent of each other
within the process.
Daemon
thread is one which serves another thread, it has no other role normally a
daemon thread carry some background program. When daemon thread remains the
program exist.
MIN_PRIORITY
= 1
NORM_PRIORITY
= 5
MAX_PRIORITY
= 10
A)
Once
a thread is stopped, it cannot be restarted. Keep in mind though that the use
of the stop() method of Thread is deprecated and should be avoided.
Class A implements Runnable{
Thread t;
Public clicker(int p){
T
= new Thread(this)
t.setPriority(p);
}
public void run(){
}
public void stop(){
}
public void start(){
t.start();
}
try{
thread.sleep(1000);
}
lo.stop();
hi.stop();
try{
hi.t.join();
lo.t.join();
}
class HiLo{
public static void main(Stirng args[]){
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
Clicker hi = new
Clicker(Thread.NORM_PRIORITY+2);
Clicker lo = new
Clicker(Thread.NORM_PRIORITY-2);
Lo.start();
Hi.start();
- Start method tell the JVM that it needs to create a
system specific thread. After creating the system resources it passes the
runnable object to it to execute the run() method.
- Calling run() method directly has the thread execute in the same as the calling
object, not a separate thread of execution.
A) Class level, method
level, object level, block level
|
Objective |
Multi Threaded Model |
Single threaded Model |
|
Local variables |
Y |
Y |
|
Instance variables |
N |
Y |
|
Class variables |
N |
N |
|
Request attributes |
Y |
Y |
|
Session attributes |
N |
N |
|
Context attributes |
N |
N |