keycloak-aplcache

diff --git a/integration/spring-security/src/main/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandler.java b/integration/spring-security/src/main/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandler.java
index d843aa7..27178ca 100644
--- a/integration/spring-security/src/main/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandler.java
+++ b/integration/spring-security/src/main/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandler.java
@@ -32,8 +32,11 @@ public class KeycloakLogoutHandler implements LogoutHandler {
 
     @Override
     public void logout(HttpServletRequest request, HttpServletResponse response, Authentication authentication) {
-
-        if (!KeycloakAuthenticationToken.class.isAssignableFrom(authentication.getClass())) {
+        if (authentication == null) {
+            log.warn("Cannot log out without authentication");
+            return;
+        }
+        else if (!KeycloakAuthenticationToken.class.isAssignableFrom(authentication.getClass())) {
             log.warn("Cannot log out a non-Keycloak authentication: {}", authentication);
             return;
         }

diff --git a/integration/spring-security/src/test/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandlerTest.java b/integration/spring-security/src/test/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandlerTest.java
index 2ee32af..6a035b5 100644
--- a/integration/spring-security/src/test/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandlerTest.java
+++ b/integration/spring-security/src/test/java/org/keycloak/adapters/springsecurity/authentication/KeycloakLogoutHandlerTest.java
@@ -89,6 +89,12 @@ public class KeycloakLogoutHandlerTest {
     }
 
     @Test
+    public void testLogoutNullAuthentication() throws Exception {
+        keycloakLogoutHandler.logout(request, response, null);
+        verifyZeroInteractions(session);
+    }
+
+    @Test
     public void testHandleSingleSignOut() throws Exception {
         keycloakLogoutHandler.handleSingleSignOut(request, response, keycloakAuthenticationToken);
         verify(session).logout(eq(keycloakDeployment));