diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/Utils.java b/runtime/Java/src/org/antlr/v4/runtime/misc/Utils.java
index ebcd7a097..44c98f51c 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/Utils.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/Utils.java
@@ -136,6 +136,7 @@ public class Utils {
 	}
 
 	public static char[] toCharArray(IntegerList data) {
+		if ( data==null ) return null;
 		return data.toCharArray();
 	}