How to update the classpath on runtime

My Application enables the user to select a directory. After this all *.class files in the directory and the subdirectories are listed. The User can now select a class to be initialised.
This works well if the selected directory is in the Classpath. If the directory is not in the classpath, I tried to update the Classpath through
System.setProperty("java.class.path",classpath).
Well as I expected, this did not affect in any way. But how can I add the new directory to the classpath of the actual VM?
Can anybody help please?

Use a custom class loader. Examples have been posted in the forums. Search for them.

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How to update the ItemRenderer at runtime..?

Hi....
am facing a hectic problem with ITemRenderes..
My requirement is like i need to insert a Label and Image in
each item of Horizontal List.
For this i created a ArrayCollection with Lable and
ImagePath. And assigning array as a Dataprovider to HorizontalList.
and am attaching itemrenderer to it (which hold the lable and
image).
code:
var data:ArrayCollection=new ArrayCollection({label:'A',
path:'a.jpg'}, {label:'B', path:'b.jpg'}{label:'C', path:'c.jpg'});
var hList:HorizontalList=new HorizontalList();
hList.dataProvider=data;
hList.itemRenderer=new ClassFactory(rendererObj);
rendererObj holds the Lable Component and Image Componnet..
Now the porblem is am trying to change the horizontal list at
runtime. Like i want to change the lable of selected item in
Horizontal list. Am able to update the arraycollection values. But
its not getting effected in ItemRenderer.
How to update the itemerenderer at runtime...?
Thanks in Advance...
Pratap

Hi Pratap,
I was playing with some sample code for this...
Here is the main.mxml
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="
http://www.adobe.com/2006/mxml"
layout="absolute">
<mx:Script>
<![CDATA[
import mx.utils.ArrayUtil;
import mx.collections.ArrayCollection;
import mx.collections.IViewCursor;
import mx.controls.Alert;
import mx.events.*;
import mx.controls.dataGridClasses.DataGridListData;
import mx.controls.listClasses.BaseListData;
import mx.controls.HorizontalList;
import mx.controls.dataGridClasses.DataGridColumn;
import mx.containers.TitleWindow;
[Bindable] private var myItemRenderer:ClassFactory;
private function doit()
myItemRenderer = new ClassFactory(rendererObj);
var mydata:ArrayCollection=new
ArrayCollection([{mylabel:'A', path:'a.jpg'}, {mylabel:'B',
path:'b.jpg'},{mylabel:'C', path:'c.jpg'}]);
var myList:HorizontalList = new HorizontalList();
myList.dataProvider = mydata;
this.addChild(myList);
myList.itemRenderer=myItemRenderer;
]]>
</mx:Script>
<mx:Button x="204" y="191" label="Button"
click="doit()"/>
</mx:Application>
Here is the rendererObj.mxml (component/itemrenderer)
<?xml version="1.0" encoding="utf-8"?>
<mx:VBox xmlns:mx="
http://www.adobe.com/2006/mxml"
width="110" height="76"
implements="mx.core.IFactory,mx.controls.listClasses.IDropInListItemRenderer"
backgroundColor="#BAB3B3" borderStyle="solid" borderThickness="3"
borderColor="#000000">
<mx:Script>
<![CDATA[
import mx.collections.IViewCursor;
import mx.controls.listClasses.BaseListData;
import mx.controls.Label;
private var _listData:BaseListData;
public function newInstance():*
return new rendererObj();
public function get listData() : BaseListData
return _listData;
public function set listData( value:BaseListData ) : void
_listData = value;
override public function set data(value:Object):void {
if (value != null)
var r:Label = new Label();
r.text = value.mylabel;
this.addChild(r);
]]>
</mx:Script>
</mx:VBox>
See how that works..you press the button and the itemrenderer
gets drawn into the horiz. list with the values from the
arraycollection.
I didnt implement the picture, but you get the idea on how to
get
the values into the hlist..
hope this helps...

Updating the CLASSPATH at runtime

Is there a way for a Java program to update the CLASSPATH environment variable?

You really shouldn't write your own class loader, if you're using JVM 1.2+. URLClassLoader works great for this purpose, and I've used it often to dynamically load classes. (Check out the link supplied by a2135 above--it allows you truly to add classes to the classpath.)
Another problem you might be having is how you are resolving the classes you want to add. For instance, I've a class name Sort, in package com.pe_gmbh.util. This :
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Walter Gildersleeve
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Freiburg, Germany

How do I set the classpath in runtime?

How can i set the classpath in runtime?
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I want to set this C:/Downloads as my classpath.
I don want to set it at the initial stage, bcoz I may have to change the downloading directory D:/Selva.
I want to access my */utils/New.gif* image available in the downloading directory by using getResource() method.

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java.net.URL[] urlarr= new java.net.URL[1];
urlarr[0]=urldir;
java.net.URLClassLoader urlcl= new java.net.URLClassLoader(urlarr); +// Here I get the Error+
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Hi everybody,
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@see http://forum.java.sun.com/thread.jsp?forum=8&thread=410868

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how to update the data in sqlserver table using procedure in biztalkserver
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How to change the classpath in rmiregistry

I am storing remote object stubs in an RMI registry as part of my application. When I try to bind my objects to the rmiregistry started by the kxs process on port 1099, I get class def not found errors because that rmiregistry does not have my classes in the classpath. My classes are in the iAS classpath because I added them through the registry.
When I start my own rmiregistry on a different port and set the classpath environment variable to include my classes, then I have no problems.
Does anyone know how to change the classpath for the rmiregistry started by the kxs process?
I am running iAS sp3 on Windows 2000 adn Solaris
Thanks,
Mark

Hi,
I would like to help, but could you kindly clarify what rmiregistry
means ?
Regards
Raj
Mark Priest wrote:
I am storing remote object stubs in an RMI registry as part of my
application. When I try to bind my objects to the rmiregistry started
by the kxs process on port 1099, I get class def not found errors
because that rmiregistry does not have my classes in the classpath.
My classes are in the iAS classpath because I added them through the
registry.
When I start my own rmiregistry on a different port and set the
classpath environment variable to include my classes, then I have no
problems.
Does anyone know how to change the classpath for the rmiregistry
started by the kxs process?
I am running iAS sp3 on Windows 2000 adn Solaris
Thanks,
Mark
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How to update the classpath on runtime

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