[SPARK-52555] Enforce UnusedLocalVariable rule

### What changes were proposed in this pull request?

This PR aims to enforce `UnusedLocalVariable` rule.

### Why are the changes needed?

To keep the code quality rule.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Pass the CIs.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #254 from dongjoon-hyun/SPARK-52555.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

config/pmd/ruleset.xml

@@ -26,7 +26,6 @@
     <exclude name="ImplicitFunctionalInterface" />
     <exclude name="UnitTestAssertionsShouldIncludeMessage" />
     <exclude name="UnitTestContainsTooManyAsserts" />
-    <exclude name="UnusedLocalVariable" />
     <exclude name="LooseCoupling" />
   </rule>
   <rule ref="category/java/codestyle.xml">

spark-operator/src/test/java/org/apache/spark/k8s/operator/SparkOperatorTest.java

@@ -142,6 +142,7 @@ void testOperatorConstructionWithDynamicConfigDisabled() {
     }
   }
 
+  @SuppressWarnings("PMD.UnusedLocalVariable")
   @Test
   void testUpdateWatchedNamespacesWithDynamicConfigEnabled() {
     MetricsSystem mockMetricsSystem = mock(MetricsSystem.class);

spark-operator/src/test/java/org/apache/spark/k8s/operator/reconciler/SparkAppReconcilerTest.java

@@ -85,6 +85,7 @@ public void beforeEach() {
         .appendNewStateAndPersist(any(SparkAppContext.class), any(ApplicationState.class));
   }
 
+  @SuppressWarnings("PMD.UnusedLocalVariable")
   @Test
   void testCleanupRunningApp() {
     try (MockedConstruction<SparkAppContext> mockAppContext =

spark-submission-worker/src/test/java/org/apache/spark/k8s/operator/SparkAppSubmissionWorkerTest.java

@@ -49,6 +49,7 @@
 import org.apache.spark.k8s.operator.status.ApplicationStatus;
 import org.apache.spark.k8s.operator.status.AttemptInfo;
 
+@SuppressWarnings("PMD.UnusedLocalVariable")
 class SparkAppSubmissionWorkerTest {
   @Test
   void buildDriverConfShouldApplySpecAndPropertiesOverride() {