Merge pull request #4354 from hmlnarik/KEYCLOAK-5241-Tomcat-Adapter-8-x-does-not-work-with-Tomcat-8-5-8

KEYCLOAK-5241 Tomcat SAML Adapter (Fix for Tomcat 8.5.8)

adapters/saml/tomcat/tomcat8/src/main/java/org/keycloak/adapters/saml/tomcat/SamlAuthenticatorValve.java

@@ -41,10 +41,20 @@ import java.util.List;
  * @version $Revision: 1 $
  */
 public class SamlAuthenticatorValve extends AbstractSamlAuthenticatorValve {
+    /**
+     * Method called by Tomcat < 8.5.5
+     */
     public boolean authenticate(Request request, HttpServletResponse response) throws IOException {
        return authenticateInternal(request, response, request.getContext().getLoginConfig());
     }
 
+    /**
+     * Method called by Tomcat >= 8.5.5
+     */
+    protected boolean doAuthenticate(Request request, HttpServletResponse response) throws IOException {
+       return this.authenticate(request, response);
+    }
+
     @Override
     protected boolean forwardToErrorPageInternal(Request request, HttpServletResponse response, Object loginConfig) throws IOException {
         if (loginConfig == null) return false;