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JavaRanch » Java Forums » Certification » Programmer Certification (SCJP/OCPJP)
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Generics

Sachin doshi
Greenhorn

Joined: Oct 04, 2006
Posts: 6
Hello,

I am studying for SCJP 5.0 from SCJP book by Kathy Sierra and Bert Bates and had a question on auto boxing in generics


Below is the code followed by mu question



This code produces something like this:

1 3 5 6 7 8 9

size 7
peek 9
size 7
poll 9
size 6
8 7 6 5 3 1 null


HOW DOES THIS WORK?

1. return two - one


2.PQsort pqs = new PQsort(); // get a Comparator
PriorityQueue<Integer> pq2 =
new PriorityQueue<Integer>(10,pqs);


3. IN THE ABOVE CODE IF I CHANGE 10 to 100 I STILL GET THE SAME RESULT, WHY?

I APPRECIATE ALL YOUR HELP

Thank you
Sachin

( tags added)
[ October 04, 2006: Message edited by: Barry Gaunt ]
Riyaz Saiyed
Greenhorn

Joined: Aug 13, 2006
Posts: 22
HOW DOES THIS WORK?

1. return two - one


compare method should return
Positive int : if first arg > then second arg.
0 or any negative : if first arg == to secong arg.
Negative int : if first arg < then second arg.


PQsort pqs = new PQsort(); // get a Comparator
PriorityQueue<Integer> pq2 =
new PriorityQueue<Integer>(10,pqs);


3. IN THE ABOVE CODE IF I CHANGE 10 to 100 I STILL GET THE SAME RESULT, WHY?



Why you expect results to be changed by changing 10 to 100....?
10 or 100 (any int in constructor) specifies initial capacity of PriorityQueue


Read the [B]javadoc if you have any doubt using method[/B]
[ October 04, 2006: Message edited by: Riyaz Saiyed ]
Riyaz Saiyed
Greenhorn

Joined: Aug 13, 2006
Posts: 22
Typo
please read as,
compare method should return
Positive int : if first argument > then second argument.
0 (Zero) : if first argument == to second argument.
Negative int : if first argument< then second argument.
Sachin doshi
Greenhorn

Joined: Oct 04, 2006
Posts: 6
Thank you Riyaz Saiyed
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: Generics
 
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