diff --git a/engine/src/main/java/org/archive/crawler/frontier/HostnameQueueAssignmentPolicy.java b/engine/src/main/java/org/archive/crawler/frontier/HostnameQueueAssignmentPolicy.java
index bba3366f..a4edd35a 100644
--- a/engine/src/main/java/org/archive/crawler/frontier/HostnameQueueAssignmentPolicy.java
+++ b/engine/src/main/java/org/archive/crawler/frontier/HostnameQueueAssignmentPolicy.java
@@ -35,7 +35,7 @@ extends URIAuthorityBasedQueueAssignmentPolicy {
     private static final long serialVersionUID = 3L;
 
     @Override
-    String getCoreKey(UURI basis) {
+    protected String getCoreKey(UURI basis) {
         String scheme = basis.getScheme();
         String candidate = null;
         try {
diff --git a/engine/src/main/java/org/archive/crawler/frontier/SurtAuthorityQueueAssignmentPolicy.java b/engine/src/main/java/org/archive/crawler/frontier/SurtAuthorityQueueAssignmentPolicy.java
index c19a3183..07178214 100644
--- a/engine/src/main/java/org/archive/crawler/frontier/SurtAuthorityQueueAssignmentPolicy.java
+++ b/engine/src/main/java/org/archive/crawler/frontier/SurtAuthorityQueueAssignmentPolicy.java
@@ -29,7 +29,7 @@ extends URIAuthorityBasedQueueAssignmentPolicy {
     private static final long serialVersionUID = 3L;
     
     @Override
-    String getCoreKey(UURI basis) {
+    protected String getCoreKey(UURI basis) {
         String candidate = getSurtAuthority(basis.getSurtForm());
         return candidate.replace(':','#');
     }
diff --git a/engine/src/main/java/org/archive/crawler/frontier/URIAuthorityBasedQueueAssignmentPolicy.java b/engine/src/main/java/org/archive/crawler/frontier/URIAuthorityBasedQueueAssignmentPolicy.java
index e6f19966..cbc49aeb 100644
--- a/engine/src/main/java/org/archive/crawler/frontier/URIAuthorityBasedQueueAssignmentPolicy.java
+++ b/engine/src/main/java/org/archive/crawler/frontier/URIAuthorityBasedQueueAssignmentPolicy.java
@@ -127,5 +127,5 @@ implements
         return path.substring(1,i);
     }
 
-    abstract String getCoreKey(UURI basis);
+    protected abstract String getCoreKey(UURI basis);
 }