RFR: JDK-8310913 Move ReferencedKeyMap to jdk.internal so it may be shared [v5]

[Mandy Chung]

On Thu, 6 Jul 2023 19:59:11 GMT, Jim Laskey <jlaskey at openjdk.org> wrote:

>> java.lang.runtime.ReferencedKeyMap was introduced to provide a concurrent caching scheme for Carrier objects. The technique used is generally useful for a variety of caching schemes and is being moved to be shared in other parts of the jdk. The MethodType interning case is one example.
>
> Jim Laskey has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add flag for reference queue type

src/java.base/share/classes/jdk/internal/util/ReferencedKeyMap.java line 107:

> 105:      *                        be used, {@link WeakReference} otherwise.
> 106:      * @param useNativeQueue  true if uses NativeReferenceQueue
> 107:      *                        otherwise use {@link ReferenceQueue}.

no such param for this constructor.

src/java.base/share/classes/jdk/internal/util/ReferencedKeyMap.java line 132:

> 130:      */
> 131:     public static <K, V> ReferencedKeyMap<K, V>
> 132:     create(boolean isSoft, boolean useNativeQueue, Supplier<Map<ReferenceKey<K>, V>> supplier) {

I suggest to keep the previous `create(boolean isSoft, Supplier supplier)`  factory method that defaults to non-native reference queue, which is commonly used.   Only `MethodType` needs to use native reference queue.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14684#discussion_r1254856896
PR Review Comment: https://git.openjdk.org/jdk/pull/14684#discussion_r1254860906