diff --git a/pkg/controller/v1alpha2/experiment/util/webhook_util.go b/pkg/controller/v1alpha2/experiment/util/webhook_util.go
index 3bffe8753f7..b50a4267615 100644
--- a/pkg/controller/v1alpha2/experiment/util/webhook_util.go
+++ b/pkg/controller/v1alpha2/experiment/util/webhook_util.go
@@ -26,12 +26,12 @@ import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	k8syaml "k8s.io/apimachinery/pkg/util/yaml"
 
-	commonapi "github.com/kubeflow/katib/pkg/api/operators/apis/common/v1alpha2"
-	ep_v1alpha2 "github.com/kubeflow/katib/pkg/api/operators/apis/experiment/v1alpha2"
+	commonapiv1alpha2 "github.com/kubeflow/katib/pkg/api/operators/apis/common/v1alpha2"
+	experimentsv1alpha2 "github.com/kubeflow/katib/pkg/api/operators/apis/experiment/v1alpha2"
 	commonv1alpha2 "github.com/kubeflow/katib/pkg/common/v1alpha2"
 )
 
-func ValidateExperiment(instance *ep_v1alpha2.Experiment) error {
+func ValidateExperiment(instance *experimentsv1alpha2.Experiment) error {
 	if !instance.IsCreated() {
 		if err := validateForCreate(instance); err != nil {
 			return err
@@ -67,17 +67,17 @@ func ValidateExperiment(instance *ep_v1alpha2.Experiment) error {
 	return nil
 }
 
-func validateAlgorithmSettings(inst *ep_v1alpha2.Experiment) error {
+func validateAlgorithmSettings(inst *experimentsv1alpha2.Experiment) error {
 	// TODO: it need call ValidateAlgorithmSettings API of vizier-core manager, implement it when vizier-core done
 	return nil
 }
 
-func validateObjective(obj *commonapi.ObjectiveSpec) error {
+func validateObjective(obj *commonapiv1alpha2.ObjectiveSpec) error {
 	if obj == nil {
 		return fmt.Errorf("No spec.objective specified.")
 	}
-	if obj.Type != commonapi.ObjectiveTypeMinimize && obj.Type != commonapi.ObjectiveTypeMaximize {
-		return fmt.Errorf("spec.objective.type must be %s or %s.", commonapi.ObjectiveTypeMinimize, commonapi.ObjectiveTypeMaximize)
+	if obj.Type != commonapiv1alpha2.ObjectiveTypeMinimize && obj.Type != commonapiv1alpha2.ObjectiveTypeMaximize {
+		return fmt.Errorf("spec.objective.type must be %s or %s.", commonapiv1alpha2.ObjectiveTypeMinimize, commonapiv1alpha2.ObjectiveTypeMaximize)
 	}
 	if obj.ObjectiveMetricName == "" {
 		return fmt.Errorf("No spec.objective.objectiveMetricName specified.")
@@ -85,7 +85,7 @@ func validateObjective(obj *commonapi.ObjectiveSpec) error {
 	return nil
 }
 
-func validateAlgorithm(ag *ep_v1alpha2.AlgorithmSpec) error {
+func validateAlgorithm(ag *experimentsv1alpha2.AlgorithmSpec) error {
 	if ag == nil {
 		return fmt.Errorf("No spec.algorithm specified.")
 	}
@@ -96,7 +96,7 @@ func validateAlgorithm(ag *ep_v1alpha2.AlgorithmSpec) error {
 	return nil
 }
 
-func validateTrialTemplate(instance *ep_v1alpha2.Experiment) error {
+func validateTrialTemplate(instance *experimentsv1alpha2.Experiment) error {
 	trialName := fmt.Sprintf("%s-trial", instance.GetName())
 	trialParams := TrialTemplateParams{
 		Experiment: instance.GetName(),
@@ -140,7 +140,7 @@ func validateSupportedJob(job *unstructured.Unstructured) error {
 	return fmt.Errorf("Job type %v not supported", gvk)
 }
 
-func validateForCreate(inst *ep_v1alpha2.Experiment) error {
+func validateForCreate(inst *experimentsv1alpha2.Experiment) error {
 	if _, err := GetExperimentFromDB(inst); err != nil {
 		if err != sql.ErrNoRows {
 			return fmt.Errorf("Fail to check record for the experiment in DB: %v", err)
@@ -151,7 +151,7 @@ func validateForCreate(inst *ep_v1alpha2.Experiment) error {
 	}
 }
 
-func validateMetricsCollector(inst *ep_v1alpha2.Experiment) error {
+func validateMetricsCollector(inst *experimentsv1alpha2.Experiment) error {
 	BUFSIZE := 1024
 	experimentName := inst.GetName()
 	trialName := fmt.Sprintf("%s-trial", inst.GetName())