diff --git a/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/InMemoryLRU.java b/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/InMemoryLRU.java
index 7f450d5..dcf7a68 100644
--- a/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/InMemoryLRU.java
+++ b/src/main/java/com/googlesource/gerrit/modules/cache/chroniclemap/InMemoryLRU.java
@@ -31,6 +31,8 @@
     LRUMap =
         Collections.synchronizedMap(
             new LinkedHashMap<K, Boolean>(capacity, 0.75f, true) {
+              private static final long serialVersionUID = 1L;
+
               @Override
               protected boolean removeEldestEntry(Map.Entry<K, Boolean> eldest) {
                 return size() > capacity;