Issue #10141 and #10142 - Reintroduce context init-param `org.eclipse…

….jetty.servlet.Default.` prefix for ee10 (#10149)

+ Issue #10141 and #10142 - Reintroduce context init-param `org.eclipse.jetty.servlet.Default.` prefix for ee10
+ Fix named servlet lookup NPE in ee10 ServletHandler.getMappedServlet
+ Adding requested javadoc

jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/DefaultServlet.java

@@ -180,6 +180,7 @@
 public class DefaultServlet extends HttpServlet
 {
     private static final Logger LOG = LoggerFactory.getLogger(DefaultServlet.class);
+    public static final String CONTEXT_INIT = "org.eclipse.jetty.servlet.Default.";
 
     private ServletContextHandler _contextHandler;
     private ServletResourceService _resourceService;
@@ -395,6 +396,29 @@ else if (gzip == Boolean.TRUE)
         return ret;
     }
 
+    /**
+     * <p>
+     *     Returns a {@code String} containing the value of the named initialization parameter, or null if the parameter does not exist.
+     * </p>
+     *
+     * <p>
+     *     Parameter lookup first checks the {@link ServletContext#getInitParameter(String)} for the
+     *     parameter prefixed with {@code org.eclipse.jetty.servlet.Default.}, then checks
+     *     {@link jakarta.servlet.ServletConfig#getInitParameter(String)} for the actual value
+     * </p>
+     *
+     * @param name a {@code String} specifying the name of the initialization parameter
+     * @return a {@code String} containing the value of the initialization parameter
+     */
+    @Override
+    public String getInitParameter(String name)
+    {
+        String value = getServletContext().getInitParameter(CONTEXT_INIT + name);
+        if (value == null)
+            value = super.getInitParameter(name);
+        return value;
+    }
+
     private Boolean getInitBoolean(String name)
     {
         String value = getInitParameter(name);

jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletHandler.java

@@ -495,6 +495,8 @@ public MatchedResource<MappedServlet> getMatchedServlet(String target)
     public MappedServlet getMappedServlet(String target)
     {
         MatchedResource<MappedServlet> matchedResource = getMatchedServlet(target);
+        if (matchedResource == null) // named servlet
+            return null;
         return matchedResource.getResource();
     }
 

jetty-ee10/jetty-ee10-servlet/src/test/java/org/eclipse/jetty/ee10/servlet/DefaultServletInitTest.java

@@ -0,0 +1,178 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.ee10.servlet;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.eclipse.jetty.http.HttpTester;
+import org.eclipse.jetty.server.LocalConnector;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.toolchain.test.FS;
+import org.eclipse.jetty.toolchain.test.jupiter.WorkDir;
+import org.eclipse.jetty.toolchain.test.jupiter.WorkDirExtension;
+import org.eclipse.jetty.util.component.LifeCycle;
+import org.eclipse.jetty.util.resource.ResourceFactory;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
+
+@ExtendWith(WorkDirExtension.class)
+public class DefaultServletInitTest
+{
+    private Server server;
+    private LocalConnector localConnector;
+
+    @AfterEach
+    public void stopServer()
+    {
+        LifeCycle.stop(server);
+    }
+
+    public void startServer(ServletContextHandler contextHandler) throws Exception
+    {
+        server = new Server();
+        localConnector = new LocalConnector(server);
+        server.addConnector(localConnector);
+        server.setHandler(contextHandler);
+        server.start();
+    }
+
+    public static class ContextInit implements Consumer<ServletContextHandler>
+    {
+        private final String key;
+        private final String value;
+
+        public ContextInit(String key, String value)
+        {
+            this.key = key;
+            this.value = value;
+        }
+
+        @Override
+        public void accept(ServletContextHandler servletContextHandler)
+        {
+            servletContextHandler.setInitParameter(key, value);
+        }
+
+        @Override
+        public String toString()
+        {
+            return "ContextInit[%s=%s]".formatted(key, value);
+        }
+    }
+
+    public static class HolderInit implements Consumer<ServletHolder>
+    {
+        private final String key;
+        private final String value;
+
+        public HolderInit(String key, String value)
+        {
+            this.key = key;
+            this.value = value;
+        }
+
+        @Override
+        public void accept(ServletHolder servletHolder)
+        {
+            servletHolder.setInitParameter(key, value);
+        }
+
+        @Override
+        public String toString()
+        {
+            return "HolderInit[%s=%s]".formatted(key, value);
+        }
+    }
+
+    public record Config(ContextInit contextInit,
+                         HolderInit holderInit)
+    {}
+
+    public static Stream<Config> welcomeServletsInitSource()
+    {
+        List<Config> configs = new ArrayList<>();
+
+        configs.add(new Config(null, new HolderInit("welcomeServlets", "true")));
+        configs.add(new Config(null, new HolderInit("welcomeServlets", "exact")));
+        configs.add(new Config(new ContextInit("org.eclipse.jetty.servlet.Default.welcomeServlets", "true"), null));
+        configs.add(new Config(new ContextInit("org.eclipse.jetty.servlet.Default.welcomeServlets", "exact"), null));
+
+        return configs.stream();
+    }
+
+    @ParameterizedTest
+    @MethodSource("welcomeServletsInitSource")
+    public void testInitWelcomeServlets(Config config, WorkDir workDir) throws Exception
+    {
+        HttpServlet testServlet = new HttpServlet()
+        {
+            @Override
+            protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
+            {
+                response.setCharacterEncoding("utf-8");
+                response.setContentType("text/plain");
+                String pathInfo = request.getPathInfo() == null ? "" : request.getPathInfo();
+                response.getWriter().println("Content from testServlet with pathInfo[" + pathInfo + "]");
+            }
+        };
+
+        Path docroot = workDir.getEmptyPathDir();
+        FS.ensureDirExists(docroot.resolve("foo"));
+
+        ServletContextHandler contextHandler = new ServletContextHandler();
+        ResourceFactory resourceFactory = ResourceFactory.of(contextHandler);
+        contextHandler.setBaseResource(resourceFactory.newResource(docroot));
+        contextHandler.setContextPath("/");
+        contextHandler.setWelcomeFiles(new String[]{"testServlet"});
+
+        ServletHolder myHolder = new ServletHolder("testServlet", testServlet);
+        contextHandler.addServlet(myHolder, "/testServlet");
+
+        ServletHolder defaultHolder = new ServletHolder("default", DefaultServlet.class);
+        contextHandler.addServlet(defaultHolder, "/");
+
+        if (config.contextInit != null)
+            config.contextInit.accept(contextHandler);
+        if (config.holderInit != null)
+            config.holderInit.accept(defaultHolder);
+
+        startServer(contextHandler);
+
+        String rawRequest = """
+            GET / HTTP/1.1
+            Host: test
+            Connection: close
+                        
+            """;
+
+        HttpTester.Response response = HttpTester.parseResponse(localConnector.getResponse(rawRequest));
+        assertThat(response.getStatus(), is(200));
+        assertThat(response.getContent(), containsString("Content from testServlet with pathInfo[]"));
+    }
+}

jetty-ee9/jetty-ee9-servlet/src/main/java/org/eclipse/jetty/ee9/servlet/DefaultServlet.java

@@ -389,6 +389,20 @@ protected ContextHandler initContextHandler(ServletContext servletContext)
             return ContextHandler.getCurrentContext().getContextHandler();
     }
 
+    /**
+     * <p>
+     *     Returns a {@code String} containing the value of the named initialization parameter, or null if the parameter does not exist.
+     * </p>
+     *
+     * <p>
+     *     Parameter lookup first checks the {@link ServletContext#getInitParameter(String)} for the
+     *     parameter prefixed with {@code org.eclipse.jetty.servlet.Default.}, then checks
+     *     {@link jakarta.servlet.ServletConfig#getInitParameter(String)} for the actual value
+     * </p>
+     *
+     * @param name a {@code String} specifying the name of the initialization parameter
+     * @return a {@code String} containing the value of the initialization parameter
+     */
     @Override
     public String getInitParameter(String name)
     {