Clone /w Generics

Question

Hi,
I appreciate there's probably a good reason for this, but could someone explain why this won't compile:
public class Copy<NAME extends Cloneable>{
   NAME _obj;
   public Copy(NAME obj){
      _obj = obj;
   public NAME getNext(){
      try{
         return (NAME) (_obj.clone());
      }catch(Exception e){
         throw new Error("Clone failed");
}throwing back at me:
Copy.java:12: cannot find symbol
symbol : method clone()
location: interface java.lang.Cloneable
return (NAME) (_obj.clone());
^
1 error
I know cloneable doesn't define clone, but last I checked Cloneable implicitly inherited from Object ....?
I know that you can get partial success with :
return (NAME) (_obj.getClass().getMethod("clone",null).invoke(_obj,null));
but then (as another thread discusses) you get unchecked exceptions.
Just wondering if there is a way to do what I want nicely?
Cheers.

Answer 1

This slightly modified program also does not compile, but it will help you to better understand what is happening here.
public class Copy<NAME extends Object & Cloneable>{
     NAME _obj;
     public Copy(NAME obj){
          _obj = obj;
     public NAME getNext(){
          try{
               return (NAME) (_obj.clone());
          }catch(Exception e){
               throw new Error("Clone failed");
}The error is:
Copy.java:9: clone() has protected access in java.lang.Object
                        return (NAME) (_obj.clone());
                                           ^
Note: Copy.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 errorYou are assuming that you can call directly clone in any Object, but not all classes have a public method clone available. A class must override clone AND make it public to enable you to call clone.