diff --git a/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/AnnotationControllerConfiguration.java b/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/AnnotationControllerConfiguration.java
index ddd69dff53..03f97982be 100644
--- a/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/AnnotationControllerConfiguration.java
+++ b/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/AnnotationControllerConfiguration.java
@@ -11,6 +11,7 @@
 import java.util.stream.Collectors;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.OperatorException;
 import io.javaoperatorsdk.operator.ReconcilerUtils;
 import io.javaoperatorsdk.operator.api.config.dependent.DependentResourceSpec;
 import io.javaoperatorsdk.operator.api.reconciler.Constants;
@@ -35,6 +36,11 @@ public class AnnotationControllerConfiguration<R extends HasMetadata>
   public AnnotationControllerConfiguration(Reconciler<R> reconciler) {
     this.reconciler = reconciler;
     this.annotation = reconciler.getClass().getAnnotation(ControllerConfiguration.class);
+    if (annotation == null) {
+      throw new OperatorException(
+          "Missing mandatory @" + ControllerConfiguration.class.getSimpleName() +
+              " annotation for reconciler:  " + reconciler);
+    }
   }
 
   @Override
diff --git a/operator-framework/src/test/java/io/javaoperatorsdk/operator/config/runtime/AnnotationControllerConfigurationTest.java b/operator-framework/src/test/java/io/javaoperatorsdk/operator/config/runtime/AnnotationControllerConfigurationTest.java
index ad97653946..fc7fb887db 100644
--- a/operator-framework/src/test/java/io/javaoperatorsdk/operator/config/runtime/AnnotationControllerConfigurationTest.java
+++ b/operator-framework/src/test/java/io/javaoperatorsdk/operator/config/runtime/AnnotationControllerConfigurationTest.java
@@ -4,9 +4,11 @@
 import java.util.Optional;
 import java.util.Set;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import io.fabric8.kubernetes.api.model.ConfigMap;
+import io.javaoperatorsdk.operator.OperatorException;
 import io.javaoperatorsdk.operator.api.config.dependent.DependentResourceSpec;
 import io.javaoperatorsdk.operator.api.reconciler.Context;
 import io.javaoperatorsdk.operator.api.reconciler.ControllerConfiguration;
@@ -77,6 +79,13 @@ void getDependentResources() {
     assertTrue(maybeConfig.get() instanceof KubernetesDependentResourceConfig);
   }
 
+  @Test
+  void missingAnnotationThrowsException() {
+    Assertions.assertThrows(OperatorException.class, () -> {
+      new AnnotationControllerConfiguration<>(new MissingAnnotationReconciler());
+    });
+  }
+
   @SuppressWarnings("rawtypes")
   private DependentResourceSpec findByName(
       List<DependentResourceSpec> dependentResourceSpecList, String name) {
@@ -157,6 +166,7 @@ public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap>
     }
   }
 
+  @ControllerConfiguration
   private static class NoDepReconciler implements Reconciler<ConfigMap> {
 
     @Override
@@ -185,4 +195,12 @@ public WithAnnotation() {
       }
     }
   }
+
+  private static class MissingAnnotationReconciler implements Reconciler<ConfigMap> {
+
+    @Override
+    public UpdateControl<ConfigMap> reconcile(ConfigMap resource, Context<ConfigMap> context) {
+      return null;
+    }
+  }
 }
diff --git a/sample-operators/webpage/src/main/java/io/javaoperatorsdk/operator/sample/WebPageStandaloneDependentsReconciler.java b/sample-operators/webpage/src/main/java/io/javaoperatorsdk/operator/sample/WebPageStandaloneDependentsReconciler.java
index 845e10bcaf..e090c6d4aa 100644
--- a/sample-operators/webpage/src/main/java/io/javaoperatorsdk/operator/sample/WebPageStandaloneDependentsReconciler.java
+++ b/sample-operators/webpage/src/main/java/io/javaoperatorsdk/operator/sample/WebPageStandaloneDependentsReconciler.java
@@ -11,14 +11,7 @@
 import io.fabric8.kubernetes.api.model.apps.Deployment;
 import io.fabric8.kubernetes.api.model.networking.v1.Ingress;
 import io.fabric8.kubernetes.client.KubernetesClient;
-import io.javaoperatorsdk.operator.api.reconciler.Context;
-import io.javaoperatorsdk.operator.api.reconciler.ControllerConfiguration;
-import io.javaoperatorsdk.operator.api.reconciler.ErrorStatusHandler;
-import io.javaoperatorsdk.operator.api.reconciler.ErrorStatusUpdateControl;
-import io.javaoperatorsdk.operator.api.reconciler.EventSourceContext;
-import io.javaoperatorsdk.operator.api.reconciler.EventSourceInitializer;
-import io.javaoperatorsdk.operator.api.reconciler.Reconciler;
-import io.javaoperatorsdk.operator.api.reconciler.UpdateControl;
+import io.javaoperatorsdk.operator.api.reconciler.*;
 import io.javaoperatorsdk.operator.processing.dependent.kubernetes.KubernetesDependentResource;
 import io.javaoperatorsdk.operator.processing.dependent.kubernetes.KubernetesDependentResourceConfig;
 import io.javaoperatorsdk.operator.processing.event.source.EventSource;