Make JsonFormat locale independent.

java/util/src/main/java/com/google/protobuf/util/Timestamps.java

@@ -44,6 +44,7 @@ import java.text.SimpleDateFormat;
 import java.util.Comparator;
 import java.util.Date;
 import java.util.GregorianCalendar;
+import java.util.Locale;
 import java.util.TimeZone;
 
 /**
@@ -83,7 +84,7 @@ public final class Timestamps {
       };
 
   private static SimpleDateFormat createTimestampFormat() {
-    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
+    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.ENGLISH);
     GregorianCalendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
     // We use Proleptic Gregorian Calendar (i.e., Gregorian calendar extends
     // backwards to year one) for timestamp formating.
@@ -386,11 +387,11 @@ public final class Timestamps {
   static String formatNanos(int nanos) {
     // Determine whether to use 3, 6, or 9 digits for the nano part.
     if (nanos % NANOS_PER_MILLISECOND == 0) {
-      return String.format("%1$03d", nanos / NANOS_PER_MILLISECOND);
+      return String.format(Locale.ENGLISH, "%1$03d", nanos / NANOS_PER_MILLISECOND);
     } else if (nanos % NANOS_PER_MICROSECOND == 0) {
-      return String.format("%1$06d", nanos / NANOS_PER_MICROSECOND);
+      return String.format(Locale.ENGLISH, "%1$06d", nanos / NANOS_PER_MICROSECOND);
     } else {
-      return String.format("%1$09d", nanos);
+      return String.format(Locale.ENGLISH, "%1$09d", nanos);
     }
   }
 }

java/util/src/test/java/com/google/protobuf/util/JsonFormatTest.java

@@ -65,10 +65,16 @@ import java.io.IOException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import junit.framework.TestCase;
 
 public class JsonFormatTest extends TestCase {
+  public JsonFormatTest() {
+    // Test that locale does not affect JsonFormat.
+    Locale.setDefault(Locale.forLanguageTag("hi-IN"));
+  }
+
   private void setAllFields(TestAllTypes.Builder builder) {
     builder.setOptionalInt32(1234);
     builder.setOptionalInt64(1234567890123456789L);