Use Seq instead of Map

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/KubernetesUtils.scala

@@ -386,14 +386,14 @@ object KubernetesUtils extends Logging {
    * This function builds the EnvVar objects for each key-value env.
    */
   @Since("3.4.0")
-  def buildEnvVars(env: Map[String, String]): Seq[EnvVar] = {
-    env.filter(env => env._2 != null)
-      .map { env =>
+  def buildEnvVars(env: Seq[(String, String)]): Seq[EnvVar] = {
+    env.filterNot(_._2 == null)
+      .map { case (k, v) =>
         new EnvVarBuilder()
-          .withName(env._1)
-          .withValue(env._2)
+          .withName(k)
+          .withValue(v)
           .build()
-      }.toSeq
+      }
   }
 
   /**

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/BasicDriverFeatureStep.scala

@@ -84,7 +84,7 @@ private[spark] class BasicDriverFeatureStep(conf: KubernetesDriverConf)
 
   override def configurePod(pod: SparkPod): SparkPod = {
     val driverCustomEnvs = KubernetesUtils.buildEnvVars(
-      Map(ENV_APPLICATION_ID -> conf.appId) ++ conf.environment)
+      Seq(ENV_APPLICATION_ID -> conf.appId) ++ conf.environment)
     val driverCpuQuantity = new Quantity(driverCoresRequest)
     val driverMemoryQuantity = new Quantity(s"${driverMemoryWithOverheadMiB}Mi")
     val maybeCpuLimitQuantity = driverLimitCores.map { limitCores =>

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/BasicExecutorFeatureStep.scala

@@ -138,7 +138,7 @@ private[spark] class BasicExecutorFeatureStep(
         (s"$ENV_JAVA_OPT_PREFIX$index", opt)
       }.toMap
       KubernetesUtils.buildEnvVars(
-        Map(
+        Seq(
           ENV_DRIVER_URL -> driverUrl,
           ENV_EXECUTOR_CORES -> execResources.cores.get.toString,
           ENV_EXECUTOR_MEMORY -> executorMemoryString,

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/DriverCommandFeatureStep.scala

@@ -86,7 +86,7 @@ private[spark] class DriverCommandFeatureStep(conf: KubernetesDriverConf)
 
     val pythonEnvs = {
       KubernetesUtils.buildEnvVars(
-        Map(
+        Seq(
           ENV_PYSPARK_PYTHON -> conf.get(PYSPARK_PYTHON)
             .orElse(environmentVariables.get(ENV_PYSPARK_PYTHON))
             .orNull,

resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/KubernetesUtilsSuite.scala

@@ -136,7 +136,7 @@ class KubernetesUtilsSuite extends SparkFunSuite with PrivateMethodTester {
         .withValue(v).build()
     }
     val outputEnvVars =
-      KubernetesUtils.buildEnvVars(input.toMap + ("testKeyForNull" -> null))
+      KubernetesUtils.buildEnvVars(input :+ ("testKeyForNull" -> null))
     assert(outputEnvVars.toSet == expectedEnvVars.toSet)
   }