Avoid boxed redirect status lookup

client/src/main/java/org/asynchttpclient/netty/handler/intercept/Interceptors.java

@@ -125,7 +125,7 @@ public boolean exitAfterIntercept(Channel channel, NettyResponseFuture<?> future
             return continue100Interceptor.exitAfterHandling100(channel, future);
         }
 
-        if (Redirect30xInterceptor.REDIRECT_STATUSES.contains(statusCode)) {
+        if (Redirect30xInterceptor.isRedirectStatus(statusCode)) {
             return redirect30xInterceptor.exitAfterHandlingRedirect(channel, future, response, request, statusCode, realm);
         }
 

client/src/main/java/org/asynchttpclient/netty/handler/intercept/Redirect30xInterceptor.java

@@ -35,9 +35,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.HashSet;
-import java.util.Set;
-
 import static io.netty.handler.codec.http.HttpHeaderNames.AUTHORIZATION;
 import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
 import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
@@ -59,17 +56,8 @@
 
 public class Redirect30xInterceptor {
 
-    public static final Set<Integer> REDIRECT_STATUSES = new HashSet<>();
     private static final Logger LOGGER = LoggerFactory.getLogger(Redirect30xInterceptor.class);
 
-    static {
-        REDIRECT_STATUSES.add(MOVED_PERMANENTLY_301);
-        REDIRECT_STATUSES.add(FOUND_302);
-        REDIRECT_STATUSES.add(SEE_OTHER_303);
-        REDIRECT_STATUSES.add(TEMPORARY_REDIRECT_307);
-        REDIRECT_STATUSES.add(PERMANENT_REDIRECT_308);
-    }
-
     private final ChannelManager channelManager;
     private final AsyncHttpClientConfig config;
     private final NettyRequestSender requestSender;
@@ -203,6 +191,14 @@ public boolean exitAfterHandlingRedirect(Channel channel, NettyResponseFuture<?>
         return false;
     }
 
+    static boolean isRedirectStatus(int statusCode) {
+        return statusCode == MOVED_PERMANENTLY_301 ||
+                statusCode == FOUND_302 ||
+                statusCode == SEE_OTHER_303 ||
+                statusCode == TEMPORARY_REDIRECT_307 ||
+                statusCode == PERMANENT_REDIRECT_308;
+    }
+
     private static HttpHeaders propagatedHeaders(Request request, Realm realm, boolean keepBody, boolean stripAuthorization) {
         HttpHeaders headers = request.getHeaders()
                 .remove(HOST)

client/src/test/java/org/asynchttpclient/netty/handler/intercept/Redirect30xInterceptorTest.java

@@ -0,0 +1,35 @@
+/*
+ *    Copyright (c) 2026 AsyncHttpClient Project. All rights reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.asynchttpclient.netty.handler.intercept;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class Redirect30xInterceptorTest {
+
+    @Test
+    public void primitiveRedirectStatusCheckMatchesRedirectStatuses() {
+        for (int statusCode : new int[]{301, 302, 303, 307, 308}) {
+            assertTrue(Redirect30xInterceptor.isRedirectStatus(statusCode), "status " + statusCode);
+        }
+
+        for (int statusCode : new int[]{100, 200, 300, 304, 305, 306, 309, 400, 500}) {
+            assertFalse(Redirect30xInterceptor.isRedirectStatus(statusCode), "status " + statusCode);
+        }
+    }
+}