[9] RFR: 8171139: Simplify ResourceBundle.CacheKey and ClassLoader may not be needed

[Naoto Sato]

Modified as:

diff -r a6d3c80ea436 
src/java.base/share/classes/java/util/ResourceBundle.java
--- a/src/java.base/share/classes/java/util/ResourceBundle.java
+++ b/src/java.base/share/classes/java/util/ResourceBundle.java
@@ -2192,7 +2192,7 @@
      private static void clearCacheImpl(Module callerModule, 
ClassLoader loader) {
          cacheList.keySet().removeIf(
              key -> key.getCallerModule() == callerModule &&
-                   getLoader(key.getModule()) == loader
+                   key.getModule() != null && 
getLoader(key.getModule()) == loader
          );
      }

This is the only occurence where CacheKey's modules are passed to 
getLoader(Module). Entire webrev is here:

http://cr.openjdk.java.net/~naoto/8171139/webrev.05/

Naoto

On 01/13/2017 04:25 PM, Mandy Chung wrote:
>
>> On Jan 13, 2017, at 4:05 PM, Naoto Sato <naoto.sato at oracle.com> wrote:
>>>
>>> Daniel asks whether there is any possibility that the target module or caller module would be GC’ed.
>>>
>>> CacheKey is copied in two places, one in findBundle and the other is putBundleInCache which is actually passed with a newly cloned CacheKey.  IIUC, the cacheKey passed to findBundle ia always a new instance (as it subsequently sets to different locale during the lookup).  Its caller module is the caller on the stack and the target module is also a strong reference either caller’s module, unnamed module from a given class loader, or a given module.
>>>
>>> Naoto will have to double check.
>>
>> I think this is correct. The current way of using CacheKey is safe from its modules to be GC'ed. However in general, it'd be good prepare them to be GC'ed. I modified the impl to hold them in local variables preventing them to be GC'ed before instantiating new References. (Also I modified not to call the other constructor in the copy constructor, reinstating some piece what Peter's diff originally had). So here is the updated webrev:
>>
>> http://cr.openjdk.java.net/~naoto/8171139/webrev.04/
>
> So callerRef and moduleRef may be null. getLoader(null) may be called which will throw NPE.
>
> Mandy
>