From 865f788612b4c5fd7fd978e346c47174750f8af4 Mon Sep 17 00:00:00 2001
From: Christoffer Hamberg <christoffer.hamberg@gmail.com>
Date: Thu, 22 Sep 2016 09:38:23 +0200
Subject: [PATCH] Caching pattern: Refactor LRU cache to avoid NPE and
 unnecessary cache lookup

---
 caching/src/main/java/com/iluwatar/caching/LruCache.java | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/caching/src/main/java/com/iluwatar/caching/LruCache.java b/caching/src/main/java/com/iluwatar/caching/LruCache.java
index 5c5549afd..4527b5548 100644
--- a/caching/src/main/java/com/iluwatar/caching/LruCache.java
+++ b/caching/src/main/java/com/iluwatar/caching/LruCache.java
@@ -136,10 +136,11 @@ public class LruCache {
    * Invalidate cache for user
    */
   public void invalidate(String userId) {
-    System.out.println("# " + userId + " has been updated! Removing older version from cache...");
-    Node toBeRemoved = cache.get(userId);
-    remove(toBeRemoved);
-    cache.remove(userId);
+    Node toBeRemoved = cache.remove(userId);
+    if (toBeRemoved != null) {
+      System.out.println("# " + userId + " has been updated! Removing older version from cache...");
+      remove(toBeRemoved);
+    }
   }
 
   public boolean isFull() {