diff --git a/core/src/main/java/org/springframework/security/util/InMemoryResource.java b/core/src/main/java/org/springframework/security/util/InMemoryResource.java
index fd374f1a5b..50c9f4ff20 100644
--- a/core/src/main/java/org/springframework/security/util/InMemoryResource.java
+++ b/core/src/main/java/org/springframework/security/util/InMemoryResource.java
@@ -68,7 +68,7 @@ public class InMemoryResource extends AbstractResource {
     }
 
     public boolean equals(Object res) {
-        if (res instanceof InMemoryResource) {
+        if (!(res instanceof InMemoryResource)) {
             return false;
         }