Tidy up module-lib API and locks

Fixing various nits.

Test: treehugger
Change-Id: I636d1b9ef084be58ea07caa0a04ba70de18a030b
diff --git a/core/java/android/timezone/TelephonyLookup.java b/core/java/android/timezone/TelephonyLookup.java
index eebccf4..8a5864e 100644
--- a/core/java/android/timezone/TelephonyLookup.java
+++ b/core/java/android/timezone/TelephonyLookup.java
@@ -30,9 +30,9 @@
  * @hide
  */
 @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
-public class TelephonyLookup {
+public final class TelephonyLookup {
 
-    private static Object sLock = new Object();
+    private static final Object sLock = new Object();
     @GuardedBy("sLock")
     private static TelephonyLookup sInstance;