Reverse the order of elements in a ArrayList

[Ramna Reddy]

Hi Ranchers,
Please give some suggestion for the following problem..
Iam working on web project,
....there is an arraylist which is filled with some data from DB...and displayed in a jsp...
My requirement is to reverse the order of elements....

Collections.reverse(List list) method is not working..

Thank you in advance...

[Ulf Dittmer]

Collections.reverse(List list) method is not working..

What does this mean? Can you give us a small example of what it does or doesn't do?

[Anup Kumar]

Collections.reverse(List list) method is not working..

You can also traverse through the arraylist in reverese order using hasPrevious() method of ListIterator.

[David O'Meara]

"Noble Coder",
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thanks,
Dave

[Ramna Reddy]

What does this mean? Can you give us a small example of what it does or doesn't do?

Hi Ulf,
When Iam applying.... Collections.reverse(myList);
The list hasn't being reversed.

[David O'Meara]

What Ulf is saying is that it works for everyone else, why doesn't is work for you?

[Ulf Dittmer]

Thanks David, that's what I was getting at.

So are you saying that this:

 
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
 
public class ReverseTest {
 
public static void main (String[] args) {
List<String> lst = new ArrayList();
lst.add("a");
lst.add("b");
 
for (String s : lst)
System.out.println(s);
 
Collections.reverse(lst);
 
for (String s : lst)
System.out.println(s);
}
} 
 

does not print

a
b
b
a

?

[David O'Meara]

My apologies, my previous post came out shorter than I wanted.

What I was trying to say is that since reverse() should work but is not, this may be indicating a further problem. Find an alternate solution rather than using reverse() is, in my opinion, working on the wrong problem and may leave you open to errors elsewhere.

Are you able to share any of the code?