here is my EXTJS code:

Code:
 var selectTrain = [{
            bodyStyle: 'padding:10px;',
            items:[{
                xtype: 'multiselect',
                fieldLabel: 'Multiselect',
                name: 'multiselect',
                width: 250,
                height: 200,
                visible: false,
                id: 'selectTrain',
                store: new Ext.data.JsonStore({
                    type: 'ajax',
                    url:'http://abc.com/xyz',
                    reader: 'json',
                    autoLoad:true      
                }),
                ddReorder: true
            }]
        }];
When I hit that URL, I am getting the following JSON:
Code:
{"54850":"5.1(1t)d1(3)","54852":"5.1(1t)a2(3)","54853":"5.1(1t)l2(1)","54841":"1.2(4)S1(1)","54789":"5.3(1)T","54849":"5.1(1t)s1(2)","54854":"5.1(1t)l2(5)","54855":"5.1(1t)s2(6)","54847":"1.1(12a)SG"}
But the multi-select box is still empty. By the way, I have added the above multi-select into a panel:

Code:
        var fp = new Ext.FormPanel({
            title: '',
            frame: true,
            labelWidth: 300,
            width: 800,
            renderTo:'report',
            bodyStyle: 'padding:0 10px 0;',
            items: [
                {
                    layout: 'column',
                    border: false,
                    // defaults are applied to all child items unless otherwise specified by child item
                    defaults: {
                        columnWidth: '1',
                        border: false
                    },            
                    items: [reportType,selectTrain]
                },
            ],
            buttons: [{
                text: 'Go'
            },{
                text: 'Reset',
                handler: function(){
                    fp.getForm().reset();
                }
            }]
        });
http://abc.com/xyz is a servlet which is using JSON.jar to convert a Vector which further consists of vectors. The code for xyz servlet is:

Code:
               PrintWriter out = response.getWriter();
               JSONObject jsonObj=new JSONObject();
               for (Iterator iterator = vec.iterator(); iterator
                    .hasNext();) {
                   Vector v = (Vector) iterator.next();
                   jsonObj.put((String)v.get(0),(String)v.get(1));

            }
               out.println(jsonObj);
Please advise on how to use proper JSON so that multi-select is populated with values?