diff --git a/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java b/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java
index d7bda32..19f19c0 100644
--- a/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java
+++ b/tests/core/runner/src/com/android/cts/runner/CtsTestRunListener.java
@@ -33,11 +33,14 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.lang.Class;
+import java.lang.ReflectiveOperationException;
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
 import java.net.Authenticator;
 import java.net.CookieHandler;
 import java.net.ResponseCache;
+import java.text.DateFormat;
 import java.util.Locale;
 import java.util.Properties;
 import java.util.TimeZone;
@@ -177,11 +180,22 @@
 
     // http://code.google.com/p/vogar/source/browse/trunk/src/vogar/target/TestEnvironment.java
     static class TestEnvironment {
+        private static final Field sDateFormatIs24HourField;
+        static {
+            try {
+                Class<?> dateFormatClass = Class.forName("java.text.DateFormat");
+                sDateFormatIs24HourField = dateFormatClass.getDeclaredField("is24Hour");
+            } catch (ReflectiveOperationException e) {
+                throw new AssertionError("Missing DateFormat.is24Hour", e);
+            }
+        }
+
         private final Locale mDefaultLocale;
         private final TimeZone mDefaultTimeZone;
         private final HostnameVerifier mHostnameVerifier;
         private final SSLSocketFactory mSslSocketFactory;
         private final Properties mProperties = new Properties();
+        private final Boolean mDefaultIs24Hour;
 
         TestEnvironment(Context context) {
             mDefaultLocale = Locale.getDefault();
@@ -196,7 +210,7 @@
             PackageManager pm = context.getPackageManager();
             mProperties.setProperty("android.cts.device.multicast",
                     Boolean.toString(pm.hasSystemFeature(PackageManager.FEATURE_WIFI)));
-
+            mDefaultIs24Hour = getDateFormatIs24Hour();
         }
 
         void reset() {
@@ -209,6 +223,23 @@
             ResponseCache.setDefault(null);
             HttpsURLConnection.setDefaultHostnameVerifier(mHostnameVerifier);
             HttpsURLConnection.setDefaultSSLSocketFactory(mSslSocketFactory);
+            setDateFormatIs24Hour(mDefaultIs24Hour);
+        }
+
+        private static Boolean getDateFormatIs24Hour() {
+            try {
+                return (Boolean) sDateFormatIs24HourField.get(null);
+            } catch (ReflectiveOperationException e) {
+                throw new AssertionError("Unable to get java.text.DateFormat.is24Hour", e);
+            }
+        }
+
+        private static void setDateFormatIs24Hour(Boolean value) {
+            try {
+                sDateFormatIs24HourField.set(null, value);
+            } catch (ReflectiveOperationException e) {
+                throw new AssertionError("Unable to set java.text.DateFormat.is24Hour", e);
+            }
         }
     }