This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
Review Questions
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13.15 |
Which one of these events will cause a thread to die? Select the one correct answer.
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13.16 |
Which statements are true about the following code? public class Joining {
static Thread createThread(final int i, final Thread t1) {
Thread t2 = new Thread() {
public void run() {
System.out.println(i+1);
try {
t1.join();
} catch (InterruptedException ie) {
}
System.out.println(i+2);
}
};
System.out.println(i+3);
t2.start();
System.out.println(i+4);
return t2;
}
public static void main(String[] args) {
createThread(10, createThread(20, Thread.currentThread()));
}
}
Select the two correct answers.
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13.17 |
Which statements are true about the following program? public class ThreadAPI {
private static Thread t1 = new Thread("T1") {
public void run() {
try { wait(1000); } catch (InterruptedException ie){}
}};
private static Thread t2 = new Thread("T2") {
public void run() {
notify();
}};
private static Thread t3 = new Thread("T3") {
public void run() {
yield();
}};
private static Thread t4 = new Thread("T4") {
public void run() {
try { sleep(100); } catch (InterruptedException ie){}
}};
public static void main(String[] args) {
t1.start(); t2.start(); t3.start(); t4.start();
try { t4.join(); } catch (InterruptedException ie){}
}
}
Select the three correct answers.
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13.18 |
Which code, when inserted at (1), will result in the program compiling and printing Done on the standard input stream, and then all threads terminating normally? public class RunningThreads {
private static Thread t1 = new Thread("T1") {
public void run() {
synchronized(RunningThreads.class) {
try {
// (1) INSERT CODE HERE ...
} catch (InterruptedException ie){
ie.printStackTrace();
}
System.out.println("Done");
}}};
public static void main(String[] args) {
t1.start();
try {
t1.join();
} catch (InterruptedException ie){
ie.printStackTrace();
}
}
}
Select the two correct answers.
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13.19 |
What can be guaranteed by calling the method yield()? Select the one correct answer.
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13.20 |
In which class or interface is the notify() method defined? Select the one correct answer.
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13.21 |
How can the priority of a thread be set? Select the one correct answer.
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13.22 |
Which statements are true about locks? Select the two correct answers.
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13.23 |
What will be the result of invoking the wait() method on an object without ensuring that the current thread holds the lock of the object? Select the one correct answer.
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13.24 |
Which of these are plausible reasons why a thread might be alive, but still not be running? Select the four correct answers.
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13.25 |
What will the following program print when compiled and run? public class Tank {
private boolean isEmpty = true;
public synchronized void emptying() {
pause(true);
isEmpty = !isEmpty;
System.out.println("emptying");
notify();
}
public synchronized void filling() {
pause(false);
isEmpty = !isEmpty;
System.out.println("filling");
notify();
}
private void pause(boolean flag) {
while(flag ? isEmpty : !isEmpty) {
try {
wait();
} catch (InterruptedException ie) {
System.out.println(Thread.currentThread() + " interrupted.");
}
}
}
public static void main(String[] args) {
final Tank token = new Tank();
(new Thread("A") { public void run() {for(;;) token.emptying();}}).start();
(new Thread("B") { public void run() {for(;;) token.filling();}}).start();
}
}
Select the one correct answer.
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13.26 |
What will the following program print when compiled and run? public class Syncher2 {
final static int[] intArray = new int[2];
private static void pause() {
while(intArray[0] == 0) {
try { intArray.wait(); }
catch (InterruptedException ie) {
System.out.println(Thread.currentThread() + " interrupted.");
}
}
}
public static void main (String[] args) {
Thread runner = new Thread() {
public void run() {
synchronized (intArray) {
pause();
System.out.println(intArray[0] + intArray[1]);
}}};
runner.start();
intArray[0] = intArray[1] = 10;
synchronized(intArray) {
intArray.notify();
}
}
}
Select the one correct answer.
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