Redirect GuardianList#toString to original toString

core-common/src/main/java/org/glassfish/jersey/internal/util/collection/GuardianStringKeyMultivaluedMap.java

@@ -381,6 +381,24 @@ public List<V> subList(int fromIndex, int toIndex) {
             final List<V> sublist = guarded.subList(fromIndex, toIndex);
             return sublist != null ? new GuardianList<>(sublist, guard) : sublist;
         }
+
+        @Override
+        public String toString() {
+            return guarded.toString();
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (GuardianList.class.isInstance(obj)) {
+                return guarded.equals(((GuardianList) obj).guarded);
+            }
+            return guarded.equals(obj);
+        }
+
+        @Override
+        public int hashCode() {
+            return guarded.hashCode();
+        }
     }
 
     private static class GuardianIterator<V> extends MutableGuardian<V> implements Iterator<V> {
@@ -411,6 +429,11 @@ public void remove() {
         public void forEachRemaining(Consumer<? super V> action) {
             guarded.forEachRemaining(action);
         }
+
+        @Override
+        public String toString() {
+            return guarded.toString();
+        }
     }
 
     private static class GuardianListIterator<V> extends GuardianIterator<V> implements ListIterator<V> {

tests/e2e/src/test/java/org/glassfish/jersey/tests/e2e/ClientTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2022 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2023 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
@@ -16,8 +16,10 @@
 
 package org.glassfish.jersey.tests.e2e;
 
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import javax.ws.rs.Consumes;
 import javax.ws.rs.GET;
@@ -32,12 +34,14 @@
 import javax.ws.rs.core.Context;
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.Variant;
 
 import org.glassfish.jersey.server.ResourceConfig;
 import org.glassfish.jersey.test.JerseyTest;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -80,6 +84,30 @@ public String contentHeaders(@HeaderParam("custom-header") final String customHe
 
             return sb.toString();
         }
+
+        @GET
+        @Path("/tostring")
+        public String headersGet(@Context HttpHeaders hs) {
+            StringBuilder sb = new StringBuilder();
+            List<String> myHeaders = Arrays.asList("Accept", "Content-Type");
+
+            try {
+                MultivaluedMap<String, String> rqhdrs = hs.getRequestHeaders();
+                Set<String> keys = rqhdrs.keySet();
+                sb.append("getRequestHeaders= ");
+                for (String header : myHeaders) {
+                    if (keys.contains(header)) {
+                        sb.append(
+                                "Found " + header + ": " + hs.getRequestHeader(header) + "; ");
+                    }
+                }
+            } catch (Throwable ex) {
+                sb.append("Unexpected exception thrown in getRequestHeaders: "
+                        + ex.getMessage());
+                ex.printStackTrace();
+            }
+            return sb.toString();
+        }
     }
 
     @Override
@@ -97,6 +125,26 @@ public void testAccesingHelloworldResource() {
         assertEquals(HelloWorldResource.MESSAGE, responseMessage);
     }
 
+    @Test
+    public void testHeadersToString() {
+        try (Response response = target("headers").path("tostring").request()
+                .header(HttpHeaders.ACCEPT, "text/*, text/html, text/html;level=1, */*")
+                .header(HttpHeaders.CONTENT_TYPE, "application/xml;charset=utf8")
+                .get()) {
+            String content = response.readEntity(String.class);
+            int index = -1;
+            Assertions.assertTrue((index = content.indexOf("getRequestHeaders=")) != -1);
+            Assertions.assertTrue((index = content.indexOf("Accept:")) != -1);
+            Assertions.assertTrue((index = content.indexOf("text/*")) != -1);
+            Assertions.assertTrue((index = content.indexOf("text/html")) != -1);
+            Assertions.assertTrue((index = content.indexOf("text/html")) != -1);
+            Assertions.assertTrue((index = content.indexOf("*/*")) != -1);
+            Assertions.assertTrue((index = content.indexOf("Content-Type:")) != -1);
+            Assertions.assertTrue((index = content.indexOf("application/xml")) != -1);
+            Assertions.assertTrue((index = content.indexOf("charset=utf8")) != -1);
+        }
+    }
+
     @Test
     public void testAccesingMissingResource() {
         final WebTarget missingResource = target().path("missing");