wei luo

Thanks, all.

What will be output by the following line of code?
System.out.println(010|4);
1) 14
2) 0
3) 6
4) 12
The answer is 4). 010 is taken as an octal number. Why can't take it as a binary one?

Thanks to everyone. It is clear to me now.

Thanks, Torgny. By the way, how long does it take to arrive you?

I prepare to take SCJP in August or September. I just find that jchq.com says the expiration of the exam is 6 months while javacaps.com says the voucher is valid for one year. Which one is true? Does that mean I can take as many times as I like within that period without paying additionally? Based on the fact that I can make most of the mock exams about 60 to 70 percent correct, how hard should I work to clear the exam? Thank you for your advice.

Many thanks to everyone.

Oh, I tested it. If we use "threadname1.start(); threadname2.start(); System.out.println("...")", the order of output is not guaranteed. but the order of outputs of the two start() are relatively fixed. Is that true?

Hi, Dave:
I tested the code as you said. But I don't understand why "end of main" comes before the two "in run". I know it must be a simple question, but I haven't got it. Thanks.

Dave, in your example, do you mean we can create a class with a static array of integers from 1 to 13, initialize it in a static block, then in constructors we need only deal with the suits? Then, is instance initializer block still the same useful?

I still can't see why initializer blocks exist? Why not just initialize variables where they are declared or in the constructors?

Thank you, everyone.

Thank you, Jason.

So the following will compile, right?
a tempa = new a();
Runnable r = tempa;

I think "final Vector v;
public AllFinals()
{ v = new Vector();
}
will also work.

Hello, every helper:
I got another three problems in go4java. Would you please help?
1)1. class Q43
2. {
3. int y=1;
4. Q43()
5. {
6. this(y);
7. }
8. Q43(int x)
9. {
10. y=x++ + ++x;
11. }
12. public static void main(String [] args)
13. {
14. Q43 t = new Q43();
15. System.out.println(t.y);
16. }
17. }
The answer is "It will give you compile time error as you cannot reference y before super class constructor has been called". I don't understand why it has relation with super class.
I think it should compile correctly and print 4.
2) 1. public class Q45
2. {
4. static
5. {
6. System.out.print("Java".startsWith(""));
7. }
8. static void processorB()
9. {
10. System.out.println(" is a boolean Operator.");
11. }
12. static Q45 processorA()
13. {
14. Q45 q=null;
15. if (("java").startsWith("null"))
16. return q;
17. else
18. return null;
19. }
20. public static void main(String[] args)
21. {
22. processorA().processorB();
23. }
24. }
The answer is "Program will compile correctly and print true is a boolean operator when executed. ". Why is there no NullPointerException? Is it because processorB() is static? If so , then we can use null object of a class to invoke its static method at any time?
3)Why don't we need to throw Exception before catching it, while if "class Except extends Exception{}" and we want to catch Except, then we must first throws it?

4) Anybody knows any site stating about initializer block and static initializer block? I am new to that.
Thanks, everyone. Have a good day.