[castor-dev] NullPointerException while marshalling java.util.Vector

[Umesh Dandekar]

Hi,
   I get the following exception when I try to marshall a
java.util.Vector that contains
java objects

MyVector.main
Caught exception java.lang.NullPointerException
java.lang.NullPointerException
        at org.apache.xml.serialize.Printer.printText(Unknown Source)
        at org.apache.xml.serialize.XMLSerializer.startElement(Unknown
Source)
        at
org.exolab.castor.xml.Marshaller.marshal(Marshaller.java:1261)
        at org.exolab.castor.xml.Marshaller.marshal(Marshaller.java:774)

        at org.exolab.castor.xml.Marshaller.marshal(Marshaller.java:663)

        at MyVector.main(MyVector.java:37)

   I have verified that the Person object can be marshalled and
unmarshalled correctly.

   The source code for this is attached with this message.

    thanks,
    ~umesh



import org.exolab.castor.xml.Marshaller;
import org.exolab.castor.xml.Unmarshaller;
import java.io.*;

import java.util.Vector;

public class MyVector implements java.io.Serializable {

   public MyVector() {
      super();
   }

   public static void main(String[] args) {
      try {
         System.out.println("MyVector.main");
                
         Vector vector = new Vector();
         Person person1 = new Person("Ryan 'Mad Dog' Madden");
         person1.setAge(40);
         vector.addElement(person1);
         Person person2 = new Person("Sachin Tendulkar");
         person2.setAge(30);
         vector.addElement(person2);

         // Create a File to marshal to
         FileWriter writer = new FileWriter("myvector.xml");

         if (vector == null) {
             System.out.println("vector is null");
         }

         if (writer == null) {
             System.out.println("writer is null");
         }

         // Marshal the person object
         Marshaller.marshal(vector, writer);
         System.out.println("MyVector.main marshalled object");

         // Create a Reader to the file to unmarshal from
         FileReader reader = new FileReader("myvector.xml");

         // Marshal the person object
         vector = (Vector)Unmarshaller.unmarshal(Vector.class, reader);
         System.out.println("MyVector.main unmarshalled object");
         System.out.println("MyVector.main myVector contains " + vector.size() + " 
elements");
         for (int ii = 0; ii < vector.size(); ii++) {
            Person person = (Person) vector.elementAt(ii);
            System.out.println("Person.main name is " + person.getName());
            System.out.println("Person.main age is " + person.getAge());
         }
      }
      catch (Throwable t) {
         System.out.println("Caught exception " + t);
         t.printStackTrace();
      }
   }
}

import java.util.Date;
import org.exolab.castor.xml.Marshaller;
import org.exolab.castor.xml.Unmarshaller;
import java.io.*;

/**
 * A simple person class
 */
public class Person implements java.io.Serializable {

   /**
     * The name of the person
     */
   private String name = null;

   /**
     * The Date of birth
     */
   private int age = 0; 

   /**
     * Creates a Person with no name
     */
   public Person() {
      super();
   }

   /**
     * Creates a Person with the given name
     */
   public Person(String name) {
      this.name  = name;
   }

   /**
     * @return age of the person
     */
   public int getAge() {
      return age;
   }

   /**
     * @return name of the person
     */
   public String getName() {
      return name;
   }

   /**
     * Sets the age of the person
     * @param age of the person
     */
   public void setAge(int age) {
      this.age = age;
   }

   /**
     * Sets the name of the person
     * @param name the name of the person
     */
   public void setName(String name) {
      this.name = name;
   }


   public static void main(String[] args) {
      try {
         System.out.println("Person.main");
         Person person = new Person("Ryan 'Mad Dog' Madden");
         person.setAge(40);

         // Create a File to marshal to
         FileWriter writer = new FileWriter("person.xml");

         // Marshal the person object
         Marshaller.marshal(person, writer);
         System.out.println("Person.main marshalled object");

         // Create a Reader to the file to unmarshal from
         FileReader reader = new FileReader("person.xml");

         // Marshal the person object
         person = (Person)Unmarshaller.unmarshal(Person.class, reader);
         System.out.println("Person.main unmarshalled object");
         System.out.println("Person.main name is " + person.getName());
         System.out.println("Person.main age is " + person.getAge());
      }
      catch (Throwable t) {
         System.out.println("Caught exception " + t);
         t.printStackTrace();
      }
   }
}