Serialization opt-in syntax (again)

[Brian Goetz]

Unfortunately I do not believe the cost is negligible.  One of the downsides of our translation approach is that serialization overhead is higher.  For inner classes, it is just a matter of tagging the class as serializable, which is negligible.  But for our approach, we would have to carry more information in the lambda itself, and the "must be serializable" constraint also rules out several possible metafactory approaches.  Also, in our approach, serializable lambdas require a lot of additional static footprint in the capturing class to deal with the potential security issues.  Also, I believe that serialization really needs to be somethign users opt explicitly into.  Foisting transparent serializaxbility on users seems rude.  

Overall I do not see this as a realistic option.  

On Oct 1, 2012, at 1:10 PM, Zakharov, Vladimir wrote:

> Excellent question. What is the cost and under what circumstances will it be incurred? I suspect, based on our experience with GS Collections, where all interfaces extend Serializable (including Predicates, Functions, etc.), the practical cost would be negligible.
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> From: lambda-spec-experts-bounces at openjdk.java.net [mailto:lambda-spec-experts-bounces at openjdk.java.net] On Behalf OfKevin Bourrillion
> Sent: Monday, October 01, 2012 12:12 PM
> To: Brian Goetz
> Cc: lambda-spec-experts at openjdk.java.net
> Subject: Re: Serialization opt-in syntax (again)
>  
> On Mon, Oct 1, 2012 at 8:57 AM, Kevin Bourrillion <kevinb at google.com> wrote:
>  
> And AFAIK, having all lambdas be serializable and having no lambdas be serializable are still not considered viable. So we're really in a tough spot.
>  
> Actually, given the horrors we're discussing here, let's be sure about this.  If all lambdas were serializable it would be a get out of jail free card for this design conundrum, so I must ask:  are we all satisfied that we have accurately quantified just how bad it would be performance-wise?  If so: how bad?
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> Kevin Bourrillion | Java Librarian | Google, Inc. | kevinb at google.com