Question

1. Analyze the following code:

public class Test implements Runnable {
  public static void main(String[] args) {
    Thread t = new Thread(this);
    t.start();
  }

  public void run() {
    System.out.println("test");
  }
}

1. The code compiles but will not print anything since t does not invoke the run method.

2. The code will not compile since you cannot invoke "this" in a static method.

3. The program compiles, runs, and prints tests on the console.

2. What will the following example print to the console?

// Test.java: Define threads using the Thread class
public class Test {
  /** Main method */
  public static void main(String[] args) {
    new Test();
  }

  public Test() {
    // Create threads
    PrintChar printA = new PrintChar('a', 4);
    PrintChar printB = new PrintChar('b', 4);

    // Start threads
    printA.run();
    printB.run();
 }

  class PrintChar implements Runnable {
    private char charToPrint; // The character to print
    private int times; // The times to repeat

    // Construct a thread with specified character and number of times to print the character
    public PrintChar(char c, int t) {
      charToPrint = c;
      times = t;
    }

    // Override the run() method to tell the system what the thread will do
    public void run() {
      for (int i = 0; i < times; i++)
        System.out.print(charToPrint);
    }
  }
}

1. ababababab

2. a and b will be printed in random order.

3. aaaaabbbbb

3. Analyze the following code:

public class Test implements Runnable {
  public static void main(String[] args) {
    Test t = new Test();
    t.start();
  }

  public void run() {}
}

1. The program compiles and runs fine.

2. The program compiles, but will not run since run method is not properly implemented.

3. The program will not compile since the Test does not implement the start method.

4. Which of the following must be true for the following code to compile

using Thread = new Thread(object)

1. object instanceof Runnable

2. object instanceof Frame

3. object instanceof Applet

5. Which of the following methods in the Thread class is deprecated?

1. yield()

2. suspend()

3. stop()

6. You can use ... to temporarily release processor time for other threads.

1. stop()

2. suspend()

3. yield()

7. Which of the following methods are defined in the Object class?

1. sleep(long)

2. yield()

3. join()

4. notify()

8.

When you run the following program what will happen?

public class Test extends Thread {
  public static void main(String[] args) {
    Test t = new Test();
    t.start();
    t.start();
  }

  public void run() {
    int a = 0;
    for(int i = 0; i < 10E10; i++) a += a + i; 
  }
}

1. java.lang.IllegalThreadStateException may occur since you started a thread even if the thread did not finish work before calling it again.

2. The program prints tests once.

3. Nothing written for console.

9. Which of the following methods in Thread can throw InterruptedException?

1. sleep(long)

2. run()

3. start()

10. Given the following code, which code snippet can be used to display time every second?

import java.util.*;

public class Test implements Runnable {
  public static void main(String[] args) {
    Thread t = new Thread(this);
    t.start();
  }

  public void run() {
    for(;;) {
      // CODE GOES HERE
      System.out.printf("%tT %n", new Date()); 
    }
  }
}

1. try { t.sleep(1000); } catch(InterruptedException e) { }

2. try { Thread.sleep(1000); } catch(InterruptedException e) { }

11. Which of the following statements is true?

1. You can use hours or thread to control animation.

2. Event action in the GUI is performed by an "event dispatcher" thread

3. If a timer and event action are running on the same thread then the time between running ActionEvent may be greater than a defined value in Timer.

  

Answer 1

1) 1. The code compiles but will not print anything since t does not invoke the run method.

2)3. aaaaabbbbb

3) 3. The program will not compile since the Test does not implement the start method.

4) using Thread = new Thread(object)

1. object instanceof Runnable

5)3. stop()

6)3. yield()

7)4. notify()

8)
1. java.lang.IllegalThreadStateException may occur since you started a thread even if the thread did not finish work before calling it again.

9) 1. sleep(long)

10) 2. try { Thread.sleep(1000); } catch(InterruptedException e) { }

}


11)
2. Event action in the GUI is performed by an "event dispatcher" thread

Thanks, PLEASE COMMENT if there is any concern.