RFR(m): JEP 269 initial API and skeleton implementation (JDK-8139232)

Stuart Marks stuart.marks at oracle.com
Thu Nov 26 00:21:18 UTC 2015

On 11/25/15 8:25 AM, Paul Benedict wrote:
> Chris, you raise a good question. Example: JPA entities stored in an immutable
> list and the list belongs to a stateful EJB that gets passivated or clustered.
> Obviously, serialization would be occuring.
> On Wed, Nov 25, 2015 at 10:14 AM, Chris Hegarty <chris.hegarty at oracle.com
> <mailto:chris.hegarty at oracle.com>> wrote:
>     Is there any impact on the Serializability of these collections, if
>     they are “value” based?  I don’t think so, but I’m not sure, since
>     their serial form is not documented.  Note to self: should we
>     document their serial form?

For JDK 9, the plan is as follows. The current API specification requires the 
collections be serializable. My plan is for the optimized implementations to use 
a common serialization proxy class; that class is the only one that will have 
its serial form documented. This preserves flexibility to change the optimized 

The collections returned by the skeleton implementation are in fact 
serializable, and this is tested by the regression tests. However, the 
serialized form is not final. I've asked the JCK team to hold off developing 
serialization tests until the serial proxy stuff gets in, at which time we can 
commit to its documented serial form.

I don't know how serialization will work in the hypothetical value-typed future. 
Using a serial proxy will, I hope, sidestep the issue of how a value type is 
represented in the serialized object stream. Of course, this assumes that the 
serialization mechanism, including proxying, continues to work similarly for 
value types as it does for ordinary objects.


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