3 files changed, 35 insertions, 3 deletions
diff --git a/luni/src/main/native/TimeZones.cpp b/luni/src/main/native/TimeZones.cpp
index bb6cee9..146f90b 100644
--- a/luni/src/main/native/TimeZones.cpp
+++ b/luni/src/main/native/TimeZones.cpp
@@ -62,8 +62,17 @@ static jobjectArray TimeZones_forCountryCode(JNIEnv* env, jclass, jstring countr
 }
 
 static jstring TimeZones_getDisplayNameImpl(JNIEnv* env, jclass, jstring javaZoneId, jboolean isDST, jint style, jstring localeId) {
+    // Get an ICU4C TimeZone* for the given id. Really, we want TimeZone::createSystemTimeZone,
+    // but that's not public. Instead, we have to check we got the time zone we wanted, rather
+    // than a clone of GMT. (http://b/3394198 asks for ICU to expose the more useful method.)
     ScopedJavaUnicodeString zoneId(env, javaZoneId);
     UniquePtr<TimeZone> zone(TimeZone::createTimeZone(zoneId.unicodeString()));
+    UnicodeString actualZoneId;
+    zone->getID(actualZoneId);
+    if (actualZoneId != zoneId.unicodeString()) {
+        return NULL;
+    }
+
     Locale locale = getLocale(env, localeId);
     // Try to get the display name of the TimeZone according to the Locale
     UnicodeString displayName;
diff --git a/luni/src/test/java/libcore/java/text/OldSimpleDateFormatTest.java b/luni/src/test/java/libcore/java/text/OldSimpleDateFormatTest.java
index 4da54e6..cbcf7e9 100644
--- a/luni/src/test/java/libcore/java/text/OldSimpleDateFormatTest.java
+++ b/luni/src/test/java/libcore/java/text/OldSimpleDateFormatTest.java
@@ -387,12 +387,24 @@ public class OldSimpleDateFormatTest extends junit.framework.TestCase {
         FormatTester test = new FormatTester();
         Calendar cal = new GregorianCalendar(1999, Calendar.JUNE, 2, 15, 3, 6);
 
-        format.setTimeZone(new SimpleTimeZone(60000, "ONE MINUTE"));
+        TimeZone tz0001 = new SimpleTimeZone(60000, "ONE MINUTE");
+        TimeZone tz0130 = new SimpleTimeZone(5400000, "ONE HOUR, THIRTY");
+        TimeZone tzMinus0130 = new SimpleTimeZone(-5400000, "NEG ONE HOUR, THIRTY");
+
+        format.setTimeZone(tz0001);
+        test.test(" Z", cal, " +0001", DateFormat.TIMEZONE_FIELD);
+        test.test(" ZZZZ", cal, " +0001", DateFormat.TIMEZONE_FIELD);
+        format.setTimeZone(tz0130);
+        test.test(" Z", cal, " +0130", DateFormat.TIMEZONE_FIELD);
+        format.setTimeZone(tzMinus0130);
+        test.test(" Z", cal, " -0130", DateFormat.TIMEZONE_FIELD);
+
+        format.setTimeZone(tz0001);
         test.test(" z", cal, " GMT+00:01", DateFormat.TIMEZONE_FIELD);
         test.test(" zzzz", cal, " GMT+00:01", DateFormat.TIMEZONE_FIELD);
-        format.setTimeZone(new SimpleTimeZone(5400000, "ONE HOUR, THIRTY"));
+        format.setTimeZone(tz0130);
         test.test(" z", cal, " GMT+01:30", DateFormat.TIMEZONE_FIELD);
-        format.setTimeZone(new SimpleTimeZone(-5400000, "NEG ONE HOUR, THIRTY"));
+        format.setTimeZone(tzMinus0130);
         test.test(" z", cal, " GMT-01:30", DateFormat.TIMEZONE_FIELD);
 
         format.setTimeZone(TimeZone.getTimeZone("America/New_York"));
diff --git a/luni/src/test/java/libcore/java/util/TimeZoneTest.java b/luni/src/test/java/libcore/java/util/TimeZoneTest.java
index dbde4ac..f7fe649 100644
--- a/luni/src/test/java/libcore/java/util/TimeZoneTest.java
+++ b/luni/src/test/java/libcore/java/util/TimeZoneTest.java
@@ -17,6 +17,7 @@
 package libcore.java.util;
 
 import java.util.Date;
+import java.util.Locale;
 import java.util.TimeZone;
 import java.util.SimpleTimeZone;
 
@@ -40,4 +41,14 @@ public class TimeZoneTest extends junit.framework.TestCase {
         stz.inDaylightTime(new Date());
         stz.clone();
     }
+
+    // http://b/3049014
+    public void testCustomTimeZoneDisplayNames() {
+        TimeZone tz0001 = new SimpleTimeZone(60000, "ONE MINUTE");
+        TimeZone tz0130 = new SimpleTimeZone(5400000, "ONE HOUR, THIRTY");
+        TimeZone tzMinus0130 = new SimpleTimeZone(-5400000, "NEG ONE HOUR, THIRTY");
+        assertEquals("GMT+00:01", tz0001.getDisplayName(false, TimeZone.SHORT, Locale.US));
+        assertEquals("GMT+01:30", tz0130.getDisplayName(false, TimeZone.SHORT, Locale.US));
+        assertEquals("GMT-01:30", tzMinus0130.getDisplayName(false, TimeZone.SHORT, Locale.US));
+    }
 }