diff --git a/javafx-ui-controls/src/javafx/scene/control/TableColumnBase.java b/javafx-ui-controls/src/javafx/scene/control/TableColumnBase.java
--- a/javafx-ui-controls/src/javafx/scene/control/TableColumnBase.java
+++ b/javafx-ui-controls/src/javafx/scene/control/TableColumnBase.java
@@ -115,7 +115,7 @@
             if (obj1 == null) return -1;
             if (obj2 == null) return 1;
             
-            if (obj1 instanceof Comparable) {
+            if (obj1 instanceof Comparable && ( obj1.getClass() == obj2.getClass() || obj1.getClass().isAssignableFrom(obj2.getClass()) )) {
                 return ((Comparable)obj1).compareTo(obj2);
             }