diff --git a/src/java/com/threerings/presents/tools/GenServiceTask.java b/src/java/com/threerings/presents/tools/GenServiceTask.java
index 0fb44b9cd..2034b16d0 100644
--- a/src/java/com/threerings/presents/tools/GenServiceTask.java
+++ b/src/java/com/threerings/presents/tools/GenServiceTask.java
@@ -143,7 +143,7 @@ public class GenServiceTask extends InvocationTask
         @Override
         public boolean equals (Object other)
         {
-            return getClass().equals(other.getClass()) &&
+            return (other != null) && getClass().equals(other.getClass()) &&
                 listener.equals(((ServiceListener)other).listener);
         }
 
diff --git a/src/java/com/threerings/presents/tools/InvocationTask.java b/src/java/com/threerings/presents/tools/InvocationTask.java
index 0c38c9332..ba6fc1cbc 100644
--- a/src/java/com/threerings/presents/tools/InvocationTask.java
+++ b/src/java/com/threerings/presents/tools/InvocationTask.java
@@ -263,11 +263,6 @@ public abstract class InvocationTask extends Task
             });
         }
 
-        public int compareTo (ServiceMethod other)
-        {
-            return getCode().compareTo(other.getCode());
-        }
-
         public String getUnwrappedArgList (boolean listenerMode)
         {
             StringBuilder buf = new StringBuilder();
@@ -315,6 +310,24 @@ public abstract class InvocationTask extends Task
                 hint.type().name() + ", " + hint.channel() + ")";
         }
 
+        // from interface Comparator<ServiceMethod>
+        public int compareTo (ServiceMethod other)
+        {
+            return getCode().compareTo(other.getCode());
+        }
+
+        @Override // from Object
+        public boolean equals (Object other)
+        {
+            return (other instanceof ServiceMethod) && compareTo((ServiceMethod)other) == 0;
+        }
+
+        @Override // from Object
+        public int hashCode ()
+        {
+            return getCode().hashCode();
+        }
+
         protected String boxArgument (Class<?> clazz, int index)
         {
             if (_ilistener.isAssignableFrom(clazz)) {