diff --git a/commons/src/main/java/fr/free/nrw/commons/category/CategorizationFragment.java b/commons/src/main/java/fr/free/nrw/commons/category/CategorizationFragment.java
index 8cedc9aa3..a76fe8d15 100644
--- a/commons/src/main/java/fr/free/nrw/commons/category/CategorizationFragment.java
+++ b/commons/src/main/java/fr/free/nrw/commons/category/CategorizationFragment.java
@@ -26,6 +26,7 @@ import java.util.ArrayList;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 
 public class CategorizationFragment extends SherlockFragment{
@@ -152,7 +153,7 @@ public class CategorizationFragment extends SherlockFragment{
 
                     if (MwVolleyApi.gpsCatExists){
                         Log.d("Cat", "GPS cats found in CategorizationFragment.java" + MwVolleyApi.getGpsCat().toString());
-                        ArrayList<String> gpsItems = new ArrayList<String>(MwVolleyApi.getGpsCat());
+                        List<String> gpsItems = new ArrayList<String>(MwVolleyApi.getGpsCat());
                         Log.d("Cat", "GPS items: " + gpsItems.toString());
 
                         mergedItems.addAll(gpsItems);
diff --git a/commons/src/main/java/fr/free/nrw/commons/upload/MwVolleyApi.java b/commons/src/main/java/fr/free/nrw/commons/upload/MwVolleyApi.java
index 2c23cf5b5..b3d21ac76 100644
--- a/commons/src/main/java/fr/free/nrw/commons/upload/MwVolleyApi.java
+++ b/commons/src/main/java/fr/free/nrw/commons/upload/MwVolleyApi.java
@@ -22,6 +22,7 @@ import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 public class MwVolleyApi {
 
@@ -30,7 +31,7 @@ public class MwVolleyApi {
     private Context context;
     private static String coordsLog;
 
-    protected static HashSet<String> categorySet;
+    protected static Set<String> categorySet;
 
     //To check later on whether any nearby categories were found
     public static boolean gpsCatExists;