On Fri, 14 Jun 2024 09:14:50 GMT, Daniel Jeliński <djelin...@openjdk.org> wrote:

>> Hi
>> 
>> This change is to improve TLS 1.3 session resumption by allowing a TLS 
>> server to send more than one resumption ticket per connection and clients to 
>> store more.  Resumption is a quick way to use an existing TLS session to 
>> establish another session by avoiding the long TLS full handshake process.  
>> In TLS 1.2 and below, clients can repeatedly resume a session by using the 
>> session ID from an established connection.  In TLS 1.3, a one-time 
>> "resumption ticket" is sent by the server after the TLS connection has been 
>> established.  The server may send multiple resumption tickets to help 
>> clients that rapidly resume connections.  If the client does not have 
>> another resumption ticket, it must go through the full TLS handshake again.  
>> The current implementation in JDK 23 and below, only sends and store one 
>> resumption ticket.
>> 
>> The number of resumption tickets a server can send should be configurable by 
>> the application developer or administrator. [RFC 
>> 8446](https://www.rfc-editor.org/rfc/rfc8446) does not specify a default 
>> value.  A system property called `jdk.tls.server.newSessionTicketCount` 
>> allows the user to change the number of resumption tickets sent by the 
>> server.  If this property is not set or given an invalid value, the default 
>> value of 3 is used. Further details are in the CSR.
>> 
>> A large portion of the changeset is on the client side by changing the 
>> caching system used by TLS.  It creates a new `CacheEntry<>` type called 
>> `QueueCacheEntry<>` that will store multiple values for a Map entry.
>
> src/java.base/share/classes/sun/security/util/Cache.java line 300:
> 
>> 298:         }
>> 299: 
>> 300:         cacheMap = new ConcurrentHashMap<>();
> 
> With LinkedHashMap we were removing least recently used entries on overflow 
> (see the implementation of `put`); with ConcurrentHashMap we will remove 
> entries in random order. Is that intentional? If it is, you might want to 
> review the class's JavaDoc.

No.  That's unfortunate about the ordering.  I was more focused on helping 
threading.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19465#discussion_r1645350766

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