Review Request JDK-8240975: Extend NativeLibraries to support explicit unloading

[Mandy Chung]

On 3/18/20 12:13 PM, Maurizio Cimadamore wrote:
>
> On 18/03/2020 18:40, Mandy Chung wrote:
>>
>>
>> On 3/18/20 11:16 AM, Maurizio Cimadamore wrote:
>>> So, maybe I'm saying something naive, but isn't the difference 
>>> between the two mechanisms mostly there to distinguish between JNI 
>>> libraries and non-JNI libraries?
>>>
>>
>> I think such distinction is kind of blurry at the moment.   One thing 
>> for sure is that JNI native method binding won't happen with the 
>> native libraries loaded through this new mechanism.
>>
>> OTOH, should JNI_OnLoad and JNI_Unload be invoked if it is a non-JNI 
>> library?  The new mechanism still does.  I expect that this will be 
>> cleared up from panama specification.
> Should defo not happen in Panama-loaded libraries

OK, I will make some adjustment to ignore JNI_OnLoad and JNI_Unload.   I 
think this is a clean distinction of these two mechanisms.


Will send an updated webrev later.

>>
>>> Or are there cases where you envision more mix and match? E.g. JNI 
>>> libraries w/o auto-unloading?
>>
>> No as unloading is important for native library loaded by custom 
>> loaders.
>>
>> I can't really think of a good static factory method name.
>>
>> would newNonJavaNativeLIbraries be slightly clearer?
>
> newJavaNativeInterfaceLibraries
>
> vs.
>
> newRawNativeLibraries
>

Both are good to me.

> could be an option.
>
> Another option, in case we do care about mix and match, would be to 
> use a builder - which would allow us to specify whether we want:
>
> * auto-unloading
> * classloader restrictions
> * calling JNI hooks
> * support linking of JNI methods
>
> But I don't think we need such level of granularity for now.
>

I don't think we need that neither.

Mandy
> Maurizio
>
>>
>> Mandy
>>>
>>> Maurizio
>>>
>>> On 18/03/2020 16:32, Mandy Chung wrote:
>>>>
>>>>
>>>> On 3/18/20 8:59 AM, Alan Bateman wrote:
>>>>> On 17/03/2020 23:09, Mandy Chung wrote:
>>>>>>
>>>>>> I have similar comment to myself and didn't come up good static 
>>>>>> factory method names.   I give it a try again: what about 
>>>>>> newNativeLibraries and newNativeLibrariesWithNoAutoUnload?
>>>>> Would newTrustedNativeLibraries work? Everything else in the 
>>>>> updated webrev looks good.
>>>>
>>>> "no auto unload" is also important.  what about 
>>>> "newTrustedNativeLibrariesNoAutoUnload" a bit long?
>>>>
>>>> Mandy
>>