Re: the new for loop for Collections does not perform the same as the Iterator for Tomcat-sessions

From:
phi <phi@gressly.ch>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 05 Sep 2007 14:05:50 +0200
Message-ID:
<46de9b9e$0$3810$5402220f@news.sunrise.ch>
GArlington schrieb:

On 5 Sep, 09:19, phi <p...@gressly.ch> wrote:

Hello

We tried the following code using JDK1.6 and tomcat 5.5 (and tomcat 6.0
as well) to enter a "note"-Object into a session.
The list-Variable is an ArrayList and therefore a Java Collection.

The new for-Loop does NOT do the job: the object "note" is always null
in the sesson.

    for(Note note : list){
                if(note.getNoteId() == noteId.intValue()){
                        session.setAttribute("note ", note);
                        break;
                }
        }

We converted to the old java style loop (using the iterator) and see:
it works!

        Iterator iter = list.iterator();
        while(iter.hasNext()){
                Note n = (Note) iter.next();
                if(n.getNoteId() == noteId.intValue()){
                        session.setAttribute("note", n);
                        break;
                }
        }

Any idea what is the differnce between the for(T t: c)-loop and the
Iterator-methods?


Is there for(T t: c) loop? Where did you find this syntax and what
does it do? I am familiar with for(init; cond; incr;) loop...


The for(<Type> <varibale> : <Collection>) - Loop is a new Construct
since JDK 1.5.
As I have mentioned, we are using JDK 1.6 (in Tomcat 6).
The for(<Type> <variable> : <Collection>) - Loop
see http://java.sun.com/j2se/1.5.0/docs/guide/language/foreach.html

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