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Threads

3

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(process)

( )

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(thread) (, , )

( ) (tasks),

( )

,

3

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:

(process

control block)

(address space)

:

context-switching

context-switching

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6

Java :

java.lang.Thread:

,

java.lang.Runnable:

run,

run Runnable, Thread( Thread Runnable)

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Threadpublic class ExampleThread extends Thread

{

public void run()

{// perform whatever thread needs to do

}

}

threadExampleThread et = new ExampleThread();et.start();

start() Thread

Thread

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Runnableinterfacepublic class ExampleRunnable implements Runnable

{

public void run()

{

// perform whatever thread needs to do

}

}

threadExampleRunnable er = new ExampleRunnable();

new Thread(er).start();

Runnable

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Ready to Run

Running

Dead

Waiting

Sleeping

Blocked

Non-runnable statesenteringnon-runnable

leaving non-runnable

terminates

scheduling

start()

timesliceends

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10

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stack space,

heap ( )

:

11

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( ) monitor( semaphore)

monitor

monitor

monitors ( mutex)

Monitor:

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(race condition) ,

( )

,

(race conditions)

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,

H Java ( ) synchronized

(race conditions)

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15

( ) :

public synchronized void xmethod {}

xmethod (blocked)

( ):

public int ymethod {

...

synchronized (this) {

... }

}

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16

(Deadlocks)

, (deadlock)

Java