[BAEL-7069] Pass list as a query parameter in Jersey (#15051)

* Pass list as a query parameter in Jersey

* Address review comment

* Address review comment

---------

Co-authored-by: rajatgarg <rajatgarg@adobe.com>

jersey/src/main/java/com/baeldung/jersey/client/listdemo/JerseyListDemo.java

@@ -0,0 +1,15 @@
+package com.baeldung.jersey.client.listdemo;
+
+import java.util.List;
+
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.QueryParam;
+
+@Path("/")
+public class JerseyListDemo {
+    @GET
+    public String getItems(@QueryParam("items") List<String> items) {
+        return "Received items: " + items;
+    }
+}

jersey/src/main/java/com/baeldung/jersey/client/listdemo/ListDemoApp.java

@@ -0,0 +1,9 @@
+package com.baeldung.jersey.client.listdemo;
+
+import org.glassfish.jersey.server.ResourceConfig;
+
+public class ListDemoApp extends ResourceConfig {
+    public ListDemoApp() {
+        packages("com.baeldung.jersey.client.listdemo");
+    }
+}

jersey/src/test/java/com/baeldung/jersey/client/listdemo/JerseyListDemoUnitTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.jersey.client.listdemo;
+
+import static org.junit.Assert.assertEquals;
+
+import java.net.URI;
+import java.util.Arrays;
+import java.util.List;
+
+import org.glassfish.jersey.test.JerseyTest;
+import org.glassfish.jersey.test.TestProperties;
+import org.junit.Test;
+
+import jakarta.ws.rs.core.Application;
+import jakarta.ws.rs.core.Response;
+import jakarta.ws.rs.core.UriBuilder;
+
+public class JerseyListDemoUnitTest  extends JerseyTest {
+
+    @Override
+    protected Application configure() {
+        enable(TestProperties.LOG_TRAFFIC);
+        enable(TestProperties.DUMP_ENTITY);
+        return new ListDemoApp();
+    }
+
+    @Test
+    public void givenList_whenUsingQueryParam_thenPassParamsAsList() {
+        Response response = target("/")
+          .queryParam("items", "item1", "item2")
+          .request()
+          .get();
+        assertEquals(Response.Status.OK.getStatusCode(), response.getStatus());
+        assertEquals("Received items: [item1, item2]", response.readEntity(String.class));
+    }
+
+    @Test
+    public void givenList_whenUsingCommaSeparatedString_thenPassParamsAsList() {
+        Response response = target("/")
+          .queryParam("items", "item1,item2")
+          .request()
+          .get();
+        assertEquals(Response.Status.OK.getStatusCode(), response.getStatus());
+        assertEquals("Received items: [item1,item2]", response.readEntity(String.class));
+    }
+
+    @Test
+    public void givenList_whenUsingUriBuilder_thenPassParamsAsList() {
+        List<String> itemsList = Arrays.asList("item1", "item2");
+        UriBuilder builder = UriBuilder.fromUri("/");
+        for (String item : itemsList) {
+            builder.queryParam("items", item);
+        }
+        URI uri = builder.build();
+        String expectedUri = "/?items=item1&items=item2";
+        assertEquals(expectedUri, uri.toString());
+    }
+}