RFR: 8316649: JMX connection timeout cannot be changed and uses the default of 0 (infinite)

[Kevin Walls]

On Thu, 23 Nov 2023 11:37:12 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> src/java.rmi/share/classes/sun/rmi/transport/tcp/TCPDirectSocketFactory.java line 46:
>> 
>>> 44:     private static final int connectTimeout =    // default 1 minute
>>> 45:         AccessController.doPrivileged((PrivilegedAction<Integer>) () ->
>>> 46:             Integer.getInteger("sun.rmi.transport.tcp.initialConnectTimeout", 60 * 1000).intValue());
>> 
>> An exception here will prevent the class from being initialized, any subsequent attempts to use the class will then produce hard to diagnose error. If the class is not loaded by the main thread, such exception/error could be swallowed unless an uncaught exception handler was registered. I would suggest implementing the logic in a static block, catch any exception and revert to default behaviour (i.e. 0) if the value supplied for the property is not an integer, or not a valid integer, etc...
>
> IIRC, the default agent uses / may use its own socket factories - are we still coming here even with those factories?

> An exception here will prevent the class from being initialized...

Maybe we can break it, but this new property is following the same pattern I think as the neighbouring file src/java.rmi/share/classes/sun/rmi/transport/tcp/TCPChannel.java when it reads the system props.  I see Integer.getInteger handles the obvious Exceptions, so specifying a strange value does not immediately break us.

If there's more protection needed then we have various other places to apply it that might need separate follow-up if you think there's a case?

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PR Review Comment: https://git.openjdk.org/jdk/pull/16771#discussion_r1403331157