Last-Modified header is garbled when accessing wadl document on Japanese locale

core-server/src/main/java/org/glassfish/jersey/server/wadl/internal/WadlResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2018 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -21,6 +21,7 @@
 import java.net.URI;
 import java.text.SimpleDateFormat;
 import java.util.Date;
+import java.util.Locale;
 
 import javax.ws.rs.GET;
 import javax.ws.rs.Path;
@@ -62,7 +63,7 @@ public final class WadlResource {
 
 
     public WadlResource() {
-        this.lastModified = new SimpleDateFormat(HTTPDATEFORMAT).format(new Date());
+        this.lastModified = new SimpleDateFormat(HTTPDATEFORMAT, Locale.US).format(new Date());
     }
 
     private boolean isCached(UriInfo uriInfo, boolean detailedWadl) {
@@ -81,7 +82,7 @@ public synchronized Response getWadl(@Context UriInfo uriInfo) {
             if ((wadlXmlRepresentation == null) || (!isCached(uriInfo, detailedWadl))) {
                 this.lastBaseUri = uriInfo.getBaseUri();
                 lastDetailedWadl = detailedWadl;
-                this.lastModified = new SimpleDateFormat(HTTPDATEFORMAT).format(new Date());
+                this.lastModified = new SimpleDateFormat(HTTPDATEFORMAT, Locale.US).format(new Date());
 
                 ApplicationDescription applicationDescription = wadlContext.getApplication(uriInfo,
                         detailedWadl);

tests/e2e-server/src/test/java/org/glassfish/jersey/tests/e2e/server/wadl/WadlResourceTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2022 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -30,6 +30,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Properties;
 import java.util.concurrent.ExecutionException;
@@ -108,6 +109,7 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -399,6 +401,20 @@ public void testLastModifiedGET() {
             assertTrue(r.getHeaders().containsKey("Last-modified"));
         }
 
+        @Test
+        public void testLastModifiedGETOnJPLocale() {
+            Locale defaultLocale = Locale.getDefault();
+            try {
+                Locale.setDefault(new Locale("ja", "JP"));
+                final WebTarget target = target("/application.wadl");
+
+                final Response r = target.queryParam(WadlUtils.DETAILED_WADL_QUERY_PARAM, "true").request().get(Response.class);
+                assertDoesNotThrow(() -> r.getLastModified());
+            } finally {
+                Locale.setDefault(defaultLocale);
+            }
+        }
+
         @Test
         public void testLastModifiedOPTIONS() {
             final WebTarget target = target("/widgets/3/verbose");