chore: add more diagnostic information

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/ExecutorServiceManager.java

@@ -31,6 +31,9 @@ public static void init(ConfigurationService configuration) {
       instance = new ExecutorServiceManager(
           new InstrumentedExecutorService(configuration.getExecutorService()),
           configuration.getTerminationTimeoutSeconds());
+      log.debug("Initialized ExecutorServiceManager executor: {}, timeout: {}",
+          configuration.getExecutorService().getClass(),
+          configuration.getTerminationTimeoutSeconds());
     } else {
       log.debug("Already started, reusing already setup instance!");
     }
@@ -47,6 +50,7 @@ public static void stop() {
 
   public static void useTestInstance() {
     if (instance == null) {
+      log.debug("Using test instance");
       instance = new ExecutorServiceManager(
           new InstrumentedExecutorService(Executors.newFixedThreadPool(5)), 1);
     }
@@ -55,7 +59,7 @@ public static void useTestInstance() {
   public static ExecutorServiceManager instance() {
     if (instance == null) {
       throw new IllegalStateException(
-          "ExecutorServiceManager hasn't been started. Call start method before using!");
+          "ExecutorServiceManager hasn't been started. Call init method before using!");
     }
     return instance;
   }
@@ -81,6 +85,9 @@ private static class InstrumentedExecutorService implements ExecutorService {
     private final ExecutorService executor;
 
     private InstrumentedExecutorService(ExecutorService executor) {
+      if (executor == null) {
+        throw new NullPointerException();
+      }
       this.executor = executor;
       debug = Utils.debugThreadPool();
     }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/Controller.java

@@ -259,6 +259,8 @@ public void start() throws OperatorException {
     final String controllerName = configuration.getName();
     final var crdName = configuration.getResourceTypeName();
     final var specVersion = "v1";
+    log.info("Starting '{}' controller for reconciler: {}, resource: {}", controllerName,
+        reconciler.getClass().getCanonicalName(), resClass.getCanonicalName());
     final var configurationService = configuration.getConfigurationService();
     try {
       // check that the custom resource is known by the cluster if configured that way