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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13.9 |
Given the following program, which statements are guaranteed to be true? public class ThreadedPrint {
static Thread makeThread(final String id, boolean daemon) {
Thread t = new Thread(id) {
public void run() {
System.out.println(id);
}
};
t.setDaemon(daemon);
t.start();
return t;
}
public static void main(String[] args) {
Thread a = makeThread("A", false);
Thread b = makeThread("B", true);
System.out.print("End\n");
}
}
Select the two correct answers.
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13.10 |
Given the following program, which alternatives would make good choices to synchronize on at (1)? public class Preference {
private int account1;
private Integer account2;
public void doIt() {
final Double account3 = new Double(10e10);
synchronized(/* ___(1)___ */) {
System.out.print("doIt");
}
}
}
Select the two correct answers.
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13.11 |
Which statements are not true about the synchronized block? Select the three correct answers.
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13.12 |
Which statement is true? Select the one correct answer.
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13.13 |
Given the following program, which statement is true? public class MyClass extends Thread {
static Object lock1 = new Object();
static Object lock2 = new Object();
static volatile int i1, i2, j1, j2, k1, k2;
public void run() { while (true) { doIt(); check(); } }
void doIt() {
synchronized(lock1) { i1++; }
j1++;
synchronized(lock2) { k1++; k2++; }
j2++;
synchronized(lock1) { i2++; }
}
void check() {
if (i1 != i2) System.out.println("i");
if (j1 != j2) System.out.println("j");
if (k1 != k2) System.out.println("k");
}
public static void main(String[] args) {
new MyClass().start();
new MyClass().start();
}
}
Select the one correct answer.
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13.14 |
Given the following program, which code modifications will result in both threads being able to participate in printing one smiley (:-)) per line continuously? public class Smiley extends Thread {
public void run() { // (1)
while(true) { // (2)
try { // (3)
System.out.print(":"); // (4)
sleep(100); // (5)
System.out.print("-"); // (6)
sleep(100); // (7)
System.out.println(")"); // (8)
sleep(100); // (9)
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
new Smiley().start();
new Smiley().start();
}
}
Select the two correct answers.
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