Review Request: loading JCE providers using ServiceLoader

[Alan Bateman]

On 13/08/2012 20:17, Sean Mullan wrote:
>
> I thought about doing that, just adding them on to the end. But there 
> are a few other subtle issues. Right now, if you want to use a JCE 
> provider that isn't registered, you instantiate it directly (as I 
> showed above). Or you could also instantiate it and use the 
> Security.addProvider or insertProviderAt methods to add it to the list 
> of registered providers. There are apps doing that today. That code 
> may break (addProvider will return -1) if we automatically registered 
> all JCE providers that were found by ServiceLoader. So I would rather 
> hold off on this and address it later with the ordering of providers. 
> We may need to adjust what it actually means for a JCE provider to be 
> installed:
I think it would make sense to add them at the end. One could imagine 
calling Signature.getInstance(algorithm) and the implementation would 
iterate over the configured providers and if none of them support the 
algorithm then it will move onto the other installed providers looking 
for one that supports this algorithm.

On the dynamic registration via Security.addProvider then I would think 
it should be an error for someone to install the provider as a service 
provider module and also attempts to register it themselves (and to 
register it themselves would require they have some means to instantiate 
it, suggesting it exports an API for that). It may be that bundled 
providers intended to be dynamically registered just don't declare 
themselves as services.

So I think it would be good to re-visit this, not critical for the 
initial push of course.

-Alan.