RFR: JDK-8222373 Improve CDS performance for custom class loaders

[Alan Bateman]

On 20/06/2019 17:50, yumin qi wrote:
> Hi, Alan and Ioi
>   Thanks. Forget to add core-libs-dev for the review.
>   If add a public API, surely it should be discussed in detail the 
> design, implementation and effects. One question, will adding a public 
> API for ClassLoader need go some process like CSR?
>   I did not add public API here and tried to avoid such process, that 
> may not be a good choice for this case.
>
You've add a protected member to java.lang.ClassLoader and also changed 
one of the protected defineClass methods to allow the class bytes be 
null so this is changing the Java SE API. But yes, API changes will 
require CSR approval. I think we first need fo figure out the right 
approach. I see Ioi's mail with a sketch of an API that provides the 
location in some form and so requires the VM/runtime to know how to read 
class bytes that that location. Providing a location and supplier of 
class bytes is another variant of that to avoid needing the VM to 
ability to load the class bytes when the class is not in the CDS 
archive. There are several options that need to be exploded to see if it 
make sense for the standard API.

-Alan