diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/Pair.java b/runtime/Java/src/org/antlr/v4/runtime/misc/Pair.java
index aa8eda9b2..2b11efd06 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/Pair.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/Pair.java
@@ -30,7 +30,9 @@
 
 package org.antlr.v4.runtime.misc;
 
-public class Pair<A,B> {
+import java.io.Serializable;
+
+public class Pair<A,B> implements Serializable {
 	public final A a;
 	public final B b;