How to clone a user-defined object?

Question

Hello,
I need to clone an Object[] array (propArray) that holds objects of Integer, Double, Boolean type, along with objects of user-defined ClassA, ClassB, ClassC type. The matter is that the ClassA object isn't being cloned, while the rest of the user-defined objects are cloned just fine.
In more detail, ClassA has two properties:
public class ClassA implements Cloneable{
   private String penaltyFor;
   private Penalty[] penaltyArray;
   protected Object clone(){
      try{
         ClassA o = (ClassA)super.clone();
         o.penaltyFor = this.penaltyFor;
//         o.penaltyArray = (Penalty[])penaltyArray.clone();  //This ain't working.
         //But neither does this :(.
         int penCount = this.penaltyArray.length;
         o.penaltyArray = new Penalty[penCount];
         for(int i = 0; i < penCount; i++)
            o.penaltyArray[i] = (Penalty)this.penaltyArray.clone();
return o;
} catch(CloneNotSupportedException e){ throw new InternalError(); }
The Penalty class contains properties of primitive type and here is its clone() method:
public class Penalty implements Cloneable{
   private String penaltyDesc;
   private int lowLimit, upperLimit, penaltyValue;
   protected Object clone(){
      try{
         Penalty o = (Penalty)super.clone();
         o.penaltyDesc = this.penaltyDesc;
         o.lowLimit = this.lowLimit;
         o.upperLimit = this.upperLimit;
         o.penaltyValue = this.penaltyValue;
         return o;
      } catch(CloneNotSupportedException e){ throw new InternalError(); }
   }I don't know what else to try. I suppose the problem is the Penalty[] array, but I may be wrong. An alternative would be to use Copy Constructors, but it will cause too many changes to the code, since the clone() method is used for the propArray copy in many places and the ClassA object is a late addition to the propArray (unfortunately it wasn't planned to exist from the beginning).
Thank's.

Answer 1

class ClassA implements Cloneable{
   private String penaltyFor;
   private Penalty[] penaltyArray;
   public Object clone(){
      try{
         ClassA o = (ClassA) super.clone();
         if (penaltyArray!=null){
            o.penaltyArray = (Penalty[]) penaltyArray.clone();
            for(int i = 0; i < penaltyArray.length; i++) {
                Penalty penalty = this.penaltyArray;
if (penalty!=null)
o.penaltyArray[i] = (Penalty) penalty.clone();
return o;
} catch(CloneNotSupportedException e){
throw new InternalError();
class Penalty implements Cloneable{
private String penaltyDesc;
private int lowLimit, upperLimit, penaltyValue;
public Object clone(){
try{
return super.clone();
} catch(CloneNotSupportedException e){
throw new InternalError();
If your Penalties are immutable, you don't need to clone them -- rather,
make then unclonable, like Strings.