diff --git a/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java b/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java
index 9b14933a8..132d9cf57 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/tree/Trees.java
@@ -163,4 +163,6 @@ public class Trees {
 		return ancestors;
 	}
 
+	private Trees() {
+	}
 }