Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/02/12/getting-information-about-a-class-using-the-objectutil-class-in-flex/ -->
<mx:Application name="ObjectUtil_getClassInfo_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.utils.ObjectUtil;
            import mx.controls.HRule;

            private function init():void {
                var obj:Object = ObjectUtil.getClassInfo(HRule);
                textArea.text = ObjectUtil.toString(obj);
            }
        ]]>
    </mx:Script>

    <mx:TextArea id="textArea"
            editable="false"
            fontSize="12"
            width="100%"
            height="100%"
            creationComplete="init();" />

</mx:Application>