diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java
index e4484c10f..493922ce4 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java
@@ -37,9 +37,11 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Set;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
@@ -560,13 +562,12 @@ public class SimpleWorkerContext extends BaseWorkerContext implements IWorkerCon
 
   @Override
   public List<String> getResourceNames() {
-    List<String> result = new ArrayList<String>();
+    Set<String> result = new HashSet<String>();
     for (StructureDefinition sd : listStructures()) {
       if (sd.getKind() == StructureDefinitionKind.RESOURCE && sd.getDerivation() == TypeDerivationRule.SPECIALIZATION)
         result.add(sd.getName());
     }
-    Collections.sort(result);
-    return result;
+    return Utilities.sorted(result);
   }
 
  
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java
index dcafaf727..508bbcb1d 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java
@@ -1297,7 +1297,7 @@ public class Utilities {
     return id.matches("[A-Za-z0-9\\-\\.]{1,64}");
   }
 
-  public static List<String> sorted(Set<String> set) {
+  public static List<String> sorted(Collection<String> set) {
     List<String> list = new ArrayList<>();
     list.addAll(set);
     Collections.sort(list);