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;
 
diff --git a/core/java/android/timezone/TelephonyNetwork.java b/core/java/android/timezone/TelephonyNetwork.java
index ae39fbd..487b3f2 100644
--- a/core/java/android/timezone/TelephonyNetwork.java
+++ b/core/java/android/timezone/TelephonyNetwork.java
@@ -27,7 +27,7 @@
  * @hide
  */
 @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
-public class TelephonyNetwork {
+public final class TelephonyNetwork {
 
     @NonNull
     private final libcore.timezone.TelephonyNetwork mDelegate;
diff --git a/core/java/android/timezone/TelephonyNetworkFinder.java b/core/java/android/timezone/TelephonyNetworkFinder.java
index 079d088..2ddd3d9 100644
--- a/core/java/android/timezone/TelephonyNetworkFinder.java
+++ b/core/java/android/timezone/TelephonyNetworkFinder.java
@@ -28,7 +28,7 @@
  * @hide
  */
 @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
-public class TelephonyNetworkFinder {
+public final class TelephonyNetworkFinder {
 
     @NonNull
     private final libcore.timezone.TelephonyNetworkFinder mDelegate;
diff --git a/core/java/android/timezone/TimeZoneFinder.java b/core/java/android/timezone/TimeZoneFinder.java
index 9327b00..c76bb1d 100644
--- a/core/java/android/timezone/TimeZoneFinder.java
+++ b/core/java/android/timezone/TimeZoneFinder.java
@@ -32,7 +32,7 @@
 @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
 public final class TimeZoneFinder {
 
-    private static Object sLock = new Object();
+    private static final Object sLock = new Object();
     @GuardedBy("sLock")
     private static TimeZoneFinder sInstance;
 
diff --git a/core/java/android/timezone/TzDataSetVersion.java b/core/java/android/timezone/TzDataSetVersion.java
index aba7c4c..605155e 100644
--- a/core/java/android/timezone/TzDataSetVersion.java
+++ b/core/java/android/timezone/TzDataSetVersion.java
@@ -89,7 +89,7 @@
      * @hide
      */
     @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
-    public static class TzDataSetException extends Exception {
+    public static final class TzDataSetException extends Exception {
 
         /** Creates an instance with a message. */
         public TzDataSetException(String message) {
diff --git a/core/java/android/timezone/ZoneInfoDb.java b/core/java/android/timezone/ZoneInfoDb.java
index eb191e8..84e9b75 100644
--- a/core/java/android/timezone/ZoneInfoDb.java
+++ b/core/java/android/timezone/ZoneInfoDb.java
@@ -32,7 +32,7 @@
 @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
 public final class ZoneInfoDb {
 
-    private static Object sLock = new Object();
+    private static final Object sLock = new Object();
     @GuardedBy("sLock")
     private static ZoneInfoDb sInstance;