Allow JMX Insight reuse for remote connections

[SylvainJuge]

When trying to reuse JMX Insight implementation in contrib (open-telemetry/opentelemetry-java-contrib#1445), the current implementation assumes that only local instances of MBeanServer are used, so we need to enable reusing it for remote connections.

Fortunately as MBeanServer (1) extends MBeanServerConnection (2), this mostly requires to replace (1) with (2).

PR initially opened as draft and does not need review for now until we have validated it works as we expect for remote connections with related PR.

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For example, for a JVM configured with JMX to listen on localhost:9999 with the following JVM arguments:

-Dcom.sun.management.jmxremote.port=9999
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

The following example code allows to capture metrics from this JVM (at least for metric registration, proper end-to-end testing will be required on consumer side).

JmxMetricInsight service = JmxMetricInsight.createService(GlobalOpenTelemetry.get(), 1000);

MetricConfiguration conf = new MetricConfiguration();

try (InputStream inputStream = Files.newInputStream(Paths.get("path/to/yaml.config"))) {
  JmxConfig config = RuleParser.get().loadConfig(inputStream);
  assertThat(config).isNotNull();

  List<JmxRule> defs = config.getRules();
  for (JmxRule rule : defs) {
    conf.addMetricDef(rule.buildMetricDef());
  }
}

service.startRemote(
    conf,
    () -> {
      try {
        JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://:9999/jmxrmi");
        JMXConnector jmxc = JMXConnectorFactory.connect(url, null);
        return Collections.singletonList(jmxc.getMBeanServerConnection());
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    });

[SylvainJuge]

@robsunday this will be required in order to be able to use remote JMX connections.

[SylvainJuge]

I've marked the PR as "ready for review" as it's working with the provided code example, so it should be quite straightforward to extend this to support other remote connection variants with certificates and authentication.

[SylvainJuge]

@PeterF778 your input might be welcome on this JMX related PR too.

[PeterF778]

Looks good. Thanks for doing this.