diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java b/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java
index 4dfc0e3a4..381896bb5 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java
@@ -75,7 +75,7 @@ public interface IntSet {
     /** remove this element from this set */
     void remove(int el);
 
-    List toList();
+    List<Integer> toList();
 
     String toString();
 }