Fix a few java code clarity warnings.

PiperOrigin-RevId: 500683667
Change-Id: Id3f3481b2f5e05a5a3eaf1ad16c9615d9adb7361

src/main/java/com/google/devtools/build/lib/skyframe/SkyframeActionExecutor.java

@@ -106,7 +106,6 @@
 import com.google.devtools.build.skyframe.SkyFunction.Environment;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.common.options.OptionsProvider;
-import java.io.Closeable;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.List;
@@ -150,7 +149,7 @@ public void injectTree(SpecialArtifact output, TreeArtifactValue tree) {
   private final SyscallCache syscallCache;
   private final Function<SkyKey, ThreadStateReceiver> threadStateReceiverFactory;
   private Reporter reporter;
-  private Map<String, String> clientEnv = ImmutableMap.of();
+  private ImmutableMap<String, String> clientEnv = ImmutableMap.of();
   private Executor executorEngine;
   private ExtendedEventHandler progressSuppressingEventHandler;
   private ActionLogBufferPathGenerator actionLogBufferPathGenerator;
@@ -529,8 +528,7 @@ private ActionExecutionContext getContext(
     boolean emitProgressEvents = shouldEmitProgressEvents(action);
     ArtifactPathResolver artifactPathResolver =
         ArtifactPathResolver.createPathResolver(actionFileSystem, executorEngine.getExecRoot());
-    FileOutErr fileOutErr;
-    fileOutErr = actionLogBufferPathGenerator.generate(artifactPathResolver);
+    FileOutErr fileOutErr = actionLogBufferPathGenerator.generate(artifactPathResolver);
     return new ActionExecutionContext(
         executorEngine,
         createFileCache(metadataHandler, actionFileSystem),
@@ -556,7 +554,7 @@ private static void closeContext(
       Action action,
       @Nullable ActionExecutionException finalException)
       throws ActionExecutionException {
-    try (Closeable c = context) {
+    try (context) {
       if (finalException != null) {
         throw finalException;
       }