Re: Java symbol confusion

"Constant Meiring" <>
23 Oct 2006 04:36:40 -0700
Thanx now I know why you have to put an object = null sometimes.

Thanx alot!


Matt Humphrey wrote:

"Constant Meiring" <> wrote in message

Hi there,

I started learning myself java a while ago and there's still loads of
concepts and things about the java language i don't know, so i may just
make an arse of myself now...

I use the NetBeans 5.0 IDE to play around with. Sometimes it does
things that I think (from what I've learned about java) that it
shouldn't do. I may just be stupid or something, so could somebody
point out my faults. Here's a piece of code:


public class Main {

   public static void main(String[] args) {

       try {
       ServerSocket serverSocket = new ServerSocket(56);

       }catch (IOException e) {System.out.println("Daar was kak in die

       Socket clientSocket = null;
       clientSocket = serverSocket.accept();

Ok that's just part of it. I'm still learning how to do the rest. Ok,
my first problem here is that when the two lines marked with arrows
above is out of the try-catch block, NetBeans tells me it can't find
the symbol serverSocket. On the other hand, when I put the two marked
lines inside of the try-catch block, it works without a problem. Can
someone explain to me why this is happening??

The name "serverSocket" is a local variable and that name exists only from
the { of the try to the } before the catch. After that } the name no longer
exists, so you can't use it within the catch expression or afterwards. Put
ServerSocket = null; before the try { and remove the ServerSocket
declaration. The name will then exist for the entire method body.

Matt Humphrey

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