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

Eamonn McManus eamonn at mcmanus.net
Sun Oct 14 21:41:12 UTC 2012

Brian Goetz <brian.goetz at oracle.com> writes:

try { clone() } catch (RuntimeException e) { ... } catch (CloneNotSupportedException e1) { .... }

I guess that means the change is not binary compatible either, since before the change the second catch block would run but after it the first one would.

Éamonn

2012/10/14 Brian Goetz <brian.goetz at oracle.com>

I believe this change is not source compatible. If a user says:

try { clone() } catch (RuntimeException e) { ... } catch (CloneNotSupportedException e1) { .... } this compiles today but would fail to compile under this change. On Oct 14, 2012, at 7:06 PM, Mike Duigou wrote: > Seems reasonable to me at first glance. I am still reviewing this but wanted to add two clarify notes: > > - This change means that CloneNotSupportedException is no longer a checked exception. This change is generally harmless. > > - Cases where CloneNotSupportedException is being caught were probably added because it was a checked exception. They can be safely left in. > > Mike > > > On Oct 14 2012, at 09:19 , Remi Forax wrote: > >> 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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