On 11/22/19 2:05 PM, Johannes Kuhn wrote:
On 22.11.2019 22:41, Remi Forax wrote:
i wonder if some codes in the wild rely on that ?
I don't think some code does, but you never know.
There is perhaps a better way, as part of the branch nestmates of
valhalla, Mandy has added a way to transfer a live object to a Class
when defining it, with that you can send all the Methods as an array
and in the bootstrap method of a condy, access to the right method by
extracting it from the array using an index.
It will avoid the whole serialization/deserialization of Methods dance.
That is a better idea - and could be done today using
Unsafe.defineAnonymousClass - If it didn't need a host class.
The new API to define a hidden class [1] replaces all existing JDK use
of Unsafe::defineAnonymousClass.
As for dynamic proxy class, it needs a mechanism to allow creating a
hidden class in an empty package. It's a separate RFE that I plan to
follow up in the future.
Here is an example:
https://gist.github.com/forax/d0f0034190bc479b86ce977fb94ca176
I believe those changes are planned for Java 14 so will be integrated
very soon.
As RDP1 is approaching fast, I think it may catch the next train.
It looks like the class is defined using
Lookup.defineHiddenClassWithClassData - in the current proxy
implementation there is no lookup object.
Also, I'm not sure if the defined proxy class needs to be findable.
Proxy class should be a hidden class as it's not intended for other
classes to symbolic reference it.
In short: I did not do an evaluation on what unspecified parts of a
proxy can be changed without breaking someones cod
IMO I see JDK-8229959 requires a couple of prototypes to understand the
pros and cons. I can't put time on this RFE at this time due to other
higher priority items.
Mandy
[1] https://bugs.openjdk.java.net/browse/JDK-8220607
