CloneNotSupportedException should extends RuntimeException not Exception (original) (raw)

Remi Forax forax at univ-mlv.fr
Sun Oct 14 16:19:16 UTC 2012

Hi everybody, CloneNotSupportedException is thrown when a developer calls Object.clone() and forget to mark the current object as Cloneable. Because it's clearly a developer error, CloneNotSupportedException should be a subtype of RuntimeException and not of Exception.

I believe this change is backward compatible because RuntimeException is a subclass of Exception, so I propose to first change CloneNotSupportedException to extends RuntimeException.

diff -r ff641c5b329b src/share/classes/java/lang/CloneNotSupportedException.java --- a/src/share/classes/java/lang/CloneNotSupportedException.java Sat Oct 13 10:15:57 2012 +0100 +++ b/src/share/classes/java/lang/CloneNotSupportedException.java Sun Oct 14 18:16:35 2012 +0200 @@ -42,7 +42,7 @@ */

public -class CloneNotSupportedException extends Exception { +class CloneNotSupportedException extends RuntimeException { private static final long serialVersionUID = 5195511250079656443L;

  /**

And then to clean up the whole JDK (in several patches) to remove all the unnecessary try/catch like the one in by example ArrayList.clone()

 public Object clone() {
     try {
         ArrayList<?> v = (ArrayList<?>) super.clone();
         v.elementData = Arrays.copyOf(elementData, size);
         v.modCount = 0;
         return v;
     } catch (CloneNotSupportedException e) {
         // this shouldn't happen, since we are Cloneable
         throw new InternalError(e);
     }
 }

will become

 public Object clone() {
     ArrayList<?> v = (ArrayList<?>) super.clone();
     v.elementData = Arrays.copyOf(elementData, size);
     v.modCount = 0;
     return v;
 }

cheers, Rémi

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