FULL PRODUCT VERSION :
java version "1.5.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_02-b09)
Java HotSpot(TM) Client VM (build 1.5.0_02-b09, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Windows XP Professional
Build 2600.xpsp2.030422-1633 (Service pack 1)

A DESCRIPTION OF THE PROBLEM :
After serializing/deserializing java.util.TreeMap$SubMap calling the entrySet() method on the resulting Map always returns null.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
serialize/deserialize instance of java.util.TreeMap$SubMap and attempt to use it (could be as simple as using it as an argument with RMI).

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Same functionallity as before serialization/deserialization
ACTUAL -
java.lang.NullPointerException


ERROR MESSAGES/STACK TRACES THAT OCCUR :
C:\>java SubmapSerializeTest
{key0=value0, key1=value1, key2=value2, key3=value3, key4=value4, key5=value5, k
ey6=value6, key7=value7, key8=value8, key9=value9}
{key2=value2, key3=value3, key4=value4, key5=value5, key6=value6, key7=value7}
java.lang.NullPointerException
        at java.util.AbstractMap.toString(AbstractMap.java:584)
        at java.lang.String.valueOf(String.java:2577)
        at java.io.PrintStream.print(PrintStream.java:616)
        at java.io.PrintStream.println(PrintStream.java:753)
        at SubmapSerializeTest.main(SubmapSerializeTest.java:25)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.*;
import java.util.*;

public class SubmapSerializeTest {

    public static void main(String[] args) {
        try {
            SortedMap map = new TreeMap();
            for (int i = 0; i < 10; i++) {
                map.put("key" + i, "value" + i);
            }
            System.out.println(map);

            ByteArrayOutputStream outputStream = new ByteArrayOutputStream(1024);
            ObjectOutputStream out = new ObjectOutputStream(outputStream);
            SortedMap serializedMap = map.subMap("key2", "key8");
            out.writeObject(serializedMap);
            out.close();
            System.out.println(serializedMap);

            byte[] byteArray = outputStream.toByteArray();
            InputStream inputStream = new ByteArrayInputStream(byteArray);
            ObjectInputStream in = new ObjectInputStream(inputStream);
            SortedMap deserializedMap = (SortedMap) in.readObject();
            System.out.println(deserializedMap);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Create a new TreeMap with all the entries from the subMap before serialization
###@###.### 2005-03-17 21:31:31 GMT