Re: Serialization of ArrayList resulting in Null Values

Patricia Shanahan <>
Sat, 24 Mar 2007 13:06:01 -0700
<eu40ba$2v7t$> wrote:

I am serializing an arraylist using the following code:


... and when I read it back in using the code below...I get the
correct number of elements in the ArrayList but the elements are all
nulll values. Any ideas??? (I have verified that the orginal list
has non-null element values.) Thanks!!!!

Perhaps an issue with the (de)serialization code for the content?

I tried the following, with a String and an Integer in my ArrayList, and
it works, with output:

java.lang.String xxx
java.lang.Integer 3

import java.util.ArrayList;

public class SerialTest {

   public static void main(String[] args) throws IOException,
ClassNotFoundException {
     // Create an ArrayList with some serializable content
     ArrayList l1 = new ArrayList();
     l1.add(new Integer(3));

     // Serialize l1 into a byte[]
     ByteArrayOutputStream outBytes = new ByteArrayOutputStream();
     ObjectOutputStream out = new ObjectOutputStream(outBytes);
     byte[] data = outBytes.toByteArray();

     // Deserialize from byte[] into l2
     ByteArrayInputStream inBytes = new ByteArrayInputStream(data);
     ObjectInputStream in = new ObjectInputStream(inBytes);
     ArrayList l2 = (ArrayList)in.readObject();

     // Print the content of the deserialized list
     for(Object o: l2){
       if(o == null){
         System.out.printf("%s %s%n",

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