diff --git a/src/com/android/launcher3/Utilities.java b/src/com/android/launcher3/Utilities.java
index 839b5e8..78774f3 100644
--- a/src/com/android/launcher3/Utilities.java
+++ b/src/com/android/launcher3/Utilities.java
@@ -60,6 +60,7 @@
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.Locale;
 import java.util.Set;
 import java.util.concurrent.Executor;
@@ -652,4 +653,14 @@
             throw new RuntimeException(e);
         }
     }
+
+    /**
+     * Returns a HashSet with a single element. We use this instead of Collections.singleton()
+     * because HashSet ensures all operations, such as remove, are supported.
+     */
+    public static <T> HashSet<T> singletonHashSet(T elem) {
+        HashSet<T> hashSet = new HashSet<>(1);
+        hashSet.add(elem);
+        return hashSet;
+    }
 }
diff --git a/src/com/android/launcher3/popup/PopupDataProvider.java b/src/com/android/launcher3/popup/PopupDataProvider.java
index 4f3b8a6..c754fda 100644
--- a/src/com/android/launcher3/popup/PopupDataProvider.java
+++ b/src/com/android/launcher3/popup/PopupDataProvider.java
@@ -22,6 +22,7 @@
 
 import com.android.launcher3.ItemInfo;
 import com.android.launcher3.Launcher;
+import com.android.launcher3.Utilities;
 import com.android.launcher3.badge.BadgeInfo;
 import com.android.launcher3.notification.NotificationInfo;
 import com.android.launcher3.notification.NotificationListener;
@@ -68,7 +69,8 @@
         } else {
             notificationWasAdded = badgeInfo.addNotificationKeyIfNotExists(notificationKey);
         }
-        updateLauncherIconBadges(Collections.singleton(postedPackageUserKey), notificationWasAdded);
+        updateLauncherIconBadges(Utilities.singletonHashSet(postedPackageUserKey),
+                notificationWasAdded);
     }
 
     @Override
@@ -78,7 +80,7 @@
             if (oldBadgeInfo.getNotificationCount() == 0) {
                 mPackageUserToBadgeInfos.remove(removedPackageUserKey);
             }
-            updateLauncherIconBadges(Collections.singleton(removedPackageUserKey));
+            updateLauncherIconBadges(Utilities.singletonHashSet(removedPackageUserKey));
 
             PopupContainerWithArrow openContainer = PopupContainerWithArrow.getOpen(mLauncher);
             if (openContainer != null) {