Clear context class loader from our threads (#14241)

Author: laurit

instrumentation/jmx-metrics/library/src/main/java/io/opentelemetry/instrumentation/jmx/engine/BeanFinder.java

@@ -35,6 +35,7 @@ class BeanFinder {
           runnable -> {
             Thread result = new Thread(runnable, "jmx_bean_finder");
             result.setDaemon(true);
+            result.setContextClassLoader(null);
             return result;
           });
   private final long discoveryDelay;

instrumentation/runtime-telemetry/runtime-telemetry-java17/library/src/main/java/io/opentelemetry/instrumentation/runtimemetrics/java17/RuntimeMetrics.java

@@ -103,6 +103,7 @@ private JfrRuntimeMetrics(OpenTelemetry openTelemetry, Predicate<JfrFeature> fea
       recordingStream.onMetadata(event -> startUpLatch.countDown());
       Thread daemonRunner = new Thread(recordingStream::start, "OpenTelemetry JFR-Metrics-Runner");
       daemonRunner.setDaemon(true);
+      daemonRunner.setContextClassLoader(null);
       daemonRunner.start();
     }
 

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/AgentInstaller.java

@@ -492,6 +492,7 @@ public void run() {
       Thread thread = new Thread(this::runAgentListeners);
       thread.setName("delayed-agent-listeners");
       thread.setDaemon(true);
+      thread.setContextClassLoader(null);
       thread.start();
     }
 

muzzle/src/main/java/io/opentelemetry/javaagent/tooling/TransformSafeLogger.java

@@ -33,6 +33,7 @@ public final class TransformSafeLogger {
       Thread thread = new Thread(new LogMessageQueueReader());
       thread.setName("otel-javaagent-transform-safe-logger");
       thread.setDaemon(true);
+      thread.setContextClassLoader(null);
       thread.start();
     } else {
       logMessageQueue = null;