Error: Could not find or load main class while parsing an XML file

I am trying to parse an XML file into java class. But it is giving me an Error saying

Could not find or load main class

The XML file which i am parsing is in same directory as the PretechDOMReader.java file

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class PretechDOMReader {
       public static void main(String[] args) {
              try {
                     File fXmlFile = new File("PretechDOM.xml");
                     DocumentBuilderFactory dbFactory = DocumentBuilderFactory
                                  .newInstance();
                     DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
                     Document doc = dBuilder.parse(fXmlFile);
                     doc.getDocumentElement().normalize();
                     System.out.println("Order Details"
                                  + doc.getDocumentElement().getNodeName());
                     NodeList nList = doc.getElementsByTagName("Ordernumber");

                     for (int temp = 0; temp < nList.getLength(); temp++) { 
                           Node nNode = nList.item(temp);

                           if (nNode.getNodeType() == Node.ELEMENT_NODE) {
                                  Element eElement = (Element) nNode;
                                  Node orderedItem1 = (Node) (NodeList) eElement
                                                .getElementsByTagName("OrderedItem1").item(0)
                                                .getChildNodes().item(0);
                                  System.out.println("OrderedItem1   :"
                                                + orderedItem1.getNodeValue());

                                  Node orderitemPrice = (Node) (NodeList) eElement
                                                .getElementsByTagName("OrderitemPrice").item(0)
                                                .getChildNodes().item(0);
                                  System.out.println("OrderitemPrice   :"
                                                + orderitemPrice.getNodeValue());
                                  Node orderitemTax = (Node) (NodeList) eElement
                                                .getElementsByTagName("OrderitemTax").item(0)
                                                .getChildNodes().item(0);
                                  System.out.println("OrderitemTax   :"
                                                + orderitemTax.getNodeValue());
                                  Node orderDiscount = (Node) (NodeList) eElement
                                                .getElementsByTagName("OrderDiscount").item(0)
                                                .getChildNodes().item(0);
                                  System.out.println("OrderDiscount   :"
                                                + orderDiscount.getNodeValue());
                           }
                     }
              } catch (Exception e) {
                     e.printStackTrace();
              }
       }

}

Here is my XML file

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Order>
    <Ordernumber Number="9988">
        <OrderedItem1>Pepsi</OrderedItem1>
        <OrderitemPrice>10</OrderitemPrice>
        <OrderitemTax>10</OrderitemTax>
        <OrderDiscount>20</OrderDiscount>
    </Ordernumber>
    <Ordernumber Number="9999">
        <OrderedItem1>Cocacola</OrderedItem1>
        <OrderitemPrice>11</OrderitemPrice>
        <OrderitemTax>11</OrderitemTax>
        <OrderDiscount>22</OrderDiscount>
    </Ordernumber>