JAVA Interview Question 10 - 20
Q. 11
11. class Alpha {
12. public void foo()
{ System.out.print(“Afoo”); }
13. }
14. public class
Beta extends Alpha {
15. public void
foo() { System.out.print(“Bfoo”); }
16. public static
void main(String[] args) {
17. Alpha a = new
Beta();
18. Beta b =
(Beta)a;
19. a.foo(); 20. b.foo();
21. }
22. }
What is the
result?
A. Afoo Afoo
B. Afoo Bfoo
C. Bfoo Afoo
D. Bfoo Bfoo
E. Compilation fails.
F. An exception is thrown at runtime.
Q. 12 Given:
7. void
waitForSignal() {
8. Object obj =
new Object();
9. synchronized(Thread.currentThreat())
{
10. obj.wait();
11. obj.notify();
12. }
13. }
Which statement is
true?
A. This code may throw an interruptedException.
B. This code may throw an illegalstateException.
C. This code may throw a TimeoutException after ten
minutes.
D. This code will not compile unless “obj.wait()” is
replaced with “((Thread) obj).wait()”.
E. Reversing the order of obj.wait() and obj.notify() may
cause this method to complete normally.
F. A call to notify() or notifyAll() from another thread
may cause this method to complete normally.
Q, 13 Given:
1. public class
TestSeven extends Thread {
2. private static
int x;
3. public
synchronized void doThings() {
4. int current =
x;
5. current++;
6. x = current;
7. }
8. public void
run() {
9. doThings();
10. }
11. }
Which statement is
true?
A. Compilation fails.
B. An exception is thrown at runtime.
C. Synchronizing the run() method would make the class
thread-safe.
D. The data in variable “x” are protected from concurrent
access problems.
E. Declaring the doThings() method as static would make
the class thread-safe.
F. Wrapping the statements within doThings() in a
synchronized (new Object()) { } block would make the class thread-safe.
Q. 14 Given:
11. public void
testIfA() {
12. if (testlfB(“True”))
{
13.
System.out.println(“True”);
14. } else {
15.
System.out.println(“Not True”);
16. }
17. }
18. public Boolean
testlfB(String str) {
19. return
Boolean.valueof(str);
20. }
What is the result
when method testlfA is invoked?
A. True
B. Not True
C. An exception is thrown at runtime.
D. Compilation fails because of an error at line 12
E. Compilation fails because of an error at line 13.
Q. 15 when
comparing java.io.BufferedWriter to java.io.FileWriter, which capability exists
as a method in only one of the two?
A. closing the stream.
B. flushing the stream
C. writing to the Stream
D. marking a location in the stream
E. writing a line separator to the stream
16. The calendar
for the year 2007 will be the same for the year.
A. 2014 B. 2016 c. 2017 D.
2018
17. A man standing
at a point P is watching the top of a tower, which makes an angle of elevation
of 30 degree with the man’s eye. The man walks some distance towards the tower
to watch its top and the angle of the elevation becomes 60 degree. What is the
distance between the base of the tower and the point P?
A. 43 units B.
8 units C. 12 units D. Data inadequate.
18. Two ships are
sailing in the sea on the two sides of a lighthouse. The angle of elevation of
the top of the lighthouse is observed from the ships are 30 degree and 45
degree respectively. If the lighthouse is 100 m high, the distance between the
two ships is:
A. 173 m B.
200 m C. 273 m D. 300 m
19. A and B take
part in 100 m race. A runs at 5 kmph. A gives B a start of 8 m and still beats
him by 8 seconds. The speed of B is:
A. 5.15 kmph B.
4.14 kmph C. 4.25 kmph D. 4.4 kmph
20. In 100 m race,
A covers the distance in 36 seconds and B in 45 seconds. In this race A beats B
by:
A. 20 m B.
25m C. 22.5m D. 9 m
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