From 1f613849886cb12f64dae76bc19b889c7ede1500 Mon Sep 17 00:00:00 2001
From: Jason Tedor <jason@tedor.me>
Date: Wed, 7 Oct 2015 10:40:22 -0400
Subject: [PATCH] Protect against null RemovalListener in setter

---
 core/src/main/java/org/elasticsearch/common/cache/Cache.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/core/src/main/java/org/elasticsearch/common/cache/Cache.java b/core/src/main/java/org/elasticsearch/common/cache/Cache.java
index a8bb4e7b641..d24bb7e424d 100644
--- a/core/src/main/java/org/elasticsearch/common/cache/Cache.java
+++ b/core/src/main/java/org/elasticsearch/common/cache/Cache.java
@@ -122,6 +122,7 @@ public class Cache<K, V> {
     }
 
     void setRemovalListener(RemovalListener<K, V> removalListener) {
+        Objects.requireNonNull(removalListener);
         this.removalListener = removalListener;
     }