Eclipse Community Forums: Objectteams » ClassCastException when instanceof is true

Help

Home

Home » Language IDEs » Objectteams » ClassCastException when instanceof is true

Show: Today's Messages :: Show Polls :: Message Navigator

ClassCastException when instanceof is true [message #506765]

Sat, 09 January 2010 18:03

Eugene Hutorny

Messages: 110
Registered: January 2010

Senior Member

The following code fails with ClassCastException on casting to Actor

		Object[] roles = getAllRoles();
		for(Object role : roles) {
			if( role instanceof Actor) {
				Actor server = (Actor) role;

The role class does not implement Actor interface but inherits its implementation from the super class
The problem disappears after adding clause 'implements Actor' to the concrete role class.

Complete sources to reproduce the problem are available on this link.

Report message to a moderator

Re: ClassCastException when instanceof is true [message #506818 is a reply to message #506765]

Sun, 10 January 2010 16:19

Stephan Herrmann

Messages: 1853
Registered: July 2009

Senior Member

Thanks for the report.

I've filed https://trac.objectteams.org/ot/ticket/333

Explanation for the curious: the two statements internally
use different versions of role Actor:
The instanceof check uses Service.Actor, this check passes.
The cast is internally translated as a call to a dynamically bound
synthetic method which then attempts a cast to Shaving.Actor,
which wrongly fails (due to a missing "implements" link in the
generated byte code).
Of course, this difference concerning Service.Actor and
Shaving.Actor shouldn't surface here.

best,
Stephan

Report message to a moderator

Previous Topic:	ClassCastException when instanceof is true
Next Topic:	Constructing instances of value-bound classes

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Thu Apr 25 08:59:17 GMT 2024

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter