diff --git a/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/KubernetesApplicationOperation.scala b/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/KubernetesApplicationOperation.scala
index 83792f52f..c569dc9dc 100644
--- a/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/KubernetesApplicationOperation.scala
+++ b/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/KubernetesApplicationOperation.scala
@@ -17,6 +17,7 @@
 
 package org.apache.kyuubi.engine
 
+import java.util.Locale
 import java.util.concurrent.{ConcurrentHashMap, TimeUnit}
 
 import com.google.common.cache.{Cache, CacheBuilder, RemovalNotification}
@@ -74,8 +75,7 @@ class KubernetesApplicationOperation extends ApplicationOperation with Logging {
 
   override def isSupported(clusterManager: Option[String]): Boolean = {
     // TODO add deploy mode to check whether is supported
-    kubernetesClient != null && clusterManager.nonEmpty &&
-    clusterManager.get.toLowerCase.startsWith("k8s")
+    kubernetesClient != null && clusterManager.exists(_.toLowerCase(Locale.ROOT).startsWith("k8s"))
   }
 
   override def killApplicationByTag(tag: String): KillResponse = {
diff --git a/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/YarnApplicationOperation.scala b/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/YarnApplicationOperation.scala
index 446314208..ea2bf6dcd 100644
--- a/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/YarnApplicationOperation.scala
+++ b/kyuubi-server/src/main/scala/org/apache/kyuubi/engine/YarnApplicationOperation.scala
@@ -17,6 +17,8 @@
 
 package org.apache.kyuubi.engine
 
+import java.util.Locale
+
 import scala.collection.JavaConverters._
 
 import org.apache.hadoop.yarn.api.records.{FinalApplicationStatus, YarnApplicationState}
@@ -46,7 +48,7 @@ class YarnApplicationOperation extends ApplicationOperation with Logging {
   }
 
   override def isSupported(clusterManager: Option[String]): Boolean = {
-    yarnClient != null && clusterManager.nonEmpty && "yarn".equalsIgnoreCase(clusterManager.get)
+    yarnClient != null && clusterManager.exists(_.toLowerCase(Locale.ROOT).startsWith("yarn"))
   }
 
   override def killApplicationByTag(tag: String): KillResponse = {