public boolean equals(Object obj)
        {
            if (this == obj)
                return true;
            if (!super.equals(obj))
                return false;
            if (getClass() != obj.getClass())
                return false;
            Elephant other = (Elephant) obj;
            if (someElephantField == null)
            {
                if (other.someElephantField != null)
                    return false;
            }
            else if (!someElephantField.equals(other.someElephantField))
                return false;
            return true;
        }
Test for polymorphic serialization.
<p>
See {@link RuntimeDerivativeField} for details.

@author David Yu
@created Jan 15, 2011
protostuff-runtime/src/test/java/io/protostuff/runtime/PolymorphicSerializationTest.java