FULL PRODUCT VERSION :
C:\home\projects\squirrel-sql\sql12\test\src>c:\tools\jdk1.6.0\bin\java -version
java version "1.6.0-beta2"
Java(TM) SE Runtime Environment (build 1.6.0-beta2-b86)
Java HotSpot(TM) Client VM (build 1.6.0-beta2-b86, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
WinXP Pro SP2

A DESCRIPTION OF THE PROBLEM :
This test code works fine in 1.5.0_06, but fails in 1.6.0 beta 2.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the code and run it.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expecting the program to exit without error.
ACTUAL -
I see the following stack trace:

Attempting to load class [Ljava.lang.String;
Exception in thread "main" java.lang.RuntimeException: java.lang.ClassNotFoundException: [Ljava.lang.String;
        at squirrel_sql.test.SerializationTest.cloneObject(SerializationTest.java:66)
        at squirrel_sql.test.SerializationTest.main(SerializationTest.java:24)
Caused by: java.lang.ClassNotFoundException: [Ljava.lang.String;
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at squirrel_sql.test.SerializationTest$1.resolveClass(SerializationTest.java:55)
        at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1575)
        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1496)
        at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1624)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1323)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
        at squirrel_sql.test.SerializationTest.cloneObject(SerializationTest.java:59)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamClass;

public class SerializeTest {

    public static void main(String[] args) throws Exception {
        String[] objs = new String[10];
        objs[0] = new String();
        String[] objs2 =
            (String[])cloneObject(objs, SerializeTest.class.getClassLoader());
    }
    
    public static Object cloneObject(Object toClone,
                                     final ClassLoader classLoader)
        throws Exception
    {
        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
        ObjectOutputStream oOut = new ObjectOutputStream(bOut);
        oOut.writeObject(toClone);
        oOut.close();
        ByteArrayInputStream bIn = new ByteArrayInputStream(bOut.toByteArray());
        bOut.close();
        ObjectInputStream oIn = new ObjectInputStream(bIn)
        {
            protected Class resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException
            {
                System.out.println("Attempting to load class "+desc.getName());
                return classLoader.loadClass(desc.getName());
            }
        };
        bIn.close();
        Object copy = oIn.readObject();
        oIn.close();
        return copy;
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Don't serialize classes that have arrays of objects as member variables.

Release Regression From : 5.0u7
The above release value was the last known release where this 
bug was not reproducible. Since then there has been a regression.