Add 1 minute fail-safe in case the class used to trigger resuming of (#8399)

remote components was already unintentionally loaded during premain.

(in such cases we may not receive a class-load callback from byte-buddy)

Author: mcculls

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/Agent.java

@@ -329,8 +329,6 @@ public void run() {
       if (appUsingCustomJMXBuilder) {
         log.debug("Custom JMX builder detected. Delaying JMXFetch initialization.");
         registerMBeanServerBuilderCallback(new StartJmxCallback(jmxStartDelay));
-        // one minute fail-safe in case nothing touches JMX and callback isn't triggered
-        scheduleJmxStart(60 + jmxStartDelay);
       } else if (appUsingCustomLogManager) {
         log.debug("Custom logger detected. Delaying JMXFetch initialization.");
         registerLogManagerCallback(new StartJmxCallback(jmxStartDelay));
@@ -437,6 +435,8 @@ public static void startDatadogTracer(InitializationTelemetry initTelemetry) thr
   }
 
   private static void registerLogManagerCallback(final ClassLoadCallBack callback) {
+    // one minute fail-safe in case the class was unintentionally loaded during premain
+    AgentTaskScheduler.INSTANCE.schedule(callback, 1, TimeUnit.MINUTES);
     try {
       final Class<?> agentInstallerClass = AGENT_CLASSLOADER.loadClass(AGENT_INSTALLER_CLASS_NAME);
       final Method registerCallbackMethod =
@@ -448,6 +448,8 @@ private static void registerLogManagerCallback(final ClassLoadCallBack callback)
   }
 
   private static void registerMBeanServerBuilderCallback(final ClassLoadCallBack callback) {
+    // one minute fail-safe in case the class was unintentionally loaded during premain
+    AgentTaskScheduler.INSTANCE.schedule(callback, 1, TimeUnit.MINUTES);
     try {
       final Class<?> agentInstallerClass = AGENT_CLASSLOADER.loadClass(AGENT_INSTALLER_CLASS_NAME);
       final Method registerCallbackMethod =
@@ -459,8 +461,14 @@ private static void registerMBeanServerBuilderCallback(final ClassLoadCallBack c
   }
 
   protected abstract static class ClassLoadCallBack implements Runnable {
+    private final AtomicBoolean starting = new AtomicBoolean();
+
     @Override
     public void run() {
+      if (starting.getAndSet(true)) {
+        return; // someone has already called us
+      }
+
       /*
        * This callback is called from within bytecode transformer. This can be a problem if callback tries
        * to load classes being transformed. To avoid this we start a thread here that calls the callback.
@@ -558,6 +566,7 @@ public void execute() {
     }
 
     private void resumeRemoteComponents() {
+      log.debug("Resuming remote components.");
       try {
         // remote components were paused for custom log-manager/jmx-builder
         // add small delay before resuming remote I/O to help stabilization