* Serialize an instance, restore it, and check for equality.
*/
public void testSerialization() {
final DefaultKeyedValues2DDataset d1 = new DefaultKeyedValues2DDataset();
d1.addValue(new Double(234.2), "Row1", "Col1");
d1.addValue(null, "Row1", "Col2");
d1.addValue(new Double(345.9), "Row2", "Col1");
d1.addValue(new Double(452.7), "Row2", "Col2");
DefaultKeyedValues2DDataset d2 = null;