fix: Disable Jetty's webapp configuration

Simplifies embedded server setup slightly, and avoid calling reflective
and ServiceLoader based configuration apis.

Fixes #6049

server/jetty/src/main/java/io/deephaven/server/jetty/JettyBackedGrpcServer.java

@@ -47,22 +47,19 @@
 import org.eclipse.jetty.servlet.DefaultServlet;
 import org.eclipse.jetty.servlet.ErrorPageErrorHandler;
 import org.eclipse.jetty.servlet.FilterHolder;
+import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.eclipse.jetty.servlet.ServletHolder;
 import org.eclipse.jetty.servlets.CrossOriginFilter;
 import org.eclipse.jetty.util.MultiException;
 import org.eclipse.jetty.util.component.Graceful;
-import org.eclipse.jetty.util.resource.Resource;
 import org.eclipse.jetty.util.ssl.SslContextFactory;
-import org.eclipse.jetty.webapp.WebAppContext;
 import org.eclipse.jetty.websocket.jakarta.common.SessionTracker;
 import org.eclipse.jetty.websocket.jakarta.server.config.JakartaWebSocketServletContainerInitializer;
 import org.eclipse.jetty.websocket.jakarta.server.internal.JakartaWebSocketServerContainer;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
 import java.io.IOException;
-import java.io.UncheckedIOException;
-import java.net.URI;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -93,17 +90,12 @@ public JettyBackedGrpcServer(
  jetty = new Server();
  jetty.addConnector(createConnector(jetty, config));
 
- final WebAppContext context =
- new WebAppContext(null, "/", null, null, null, new ErrorPageErrorHandler(), NO_SESSIONS);
- try {
- String knownFile = "/ide/index.html";
- URL ide = JettyBackedGrpcServer.class.getResource(knownFile);
- Resource jarContents = Resource.newResource(ide.toExternalForm().replace("!" + knownFile, "!/"));
- context.setBaseResource(ControlledCacheResource.wrap(jarContents));
- } catch (IOException ioException) {
- throw new UncheckedIOException(ioException);
- }
- context.setInitParameter(DefaultServlet.CONTEXT_INIT + "dirAllowed", "false");
+ final ServletContextHandler context =
+ new ServletContextHandler(null, "/", null, null, null, new ErrorPageErrorHandler(), NO_SESSIONS);
+ String knownFile = "/ide/index.html";
+ URL ide = JettyBackedGrpcServer.class.getResource(knownFile);
+ String path = ide.toExternalForm().replace("!" + knownFile, "!/");
+ context.addServlet(servletHolder("default", path), "/*");
 
  // Cache all of the appropriate assets folders
  for (String appRoot : List.of("/ide/", "/iframe/table/", "/iframe/chart/", "/iframe/widget/")) {
@@ -178,7 +170,7 @@ public JettyBackedGrpcServer(
  // Wire up /js-plugins/*
  // TODO(deephaven-core#4620): Add js-plugins version-aware caching
  context.addFilter(NoCacheFilter.class, JS_PLUGINS_PATH_SPEC, EnumSet.noneOf(DispatcherType.class));
- context.addServlet(servletHolder("js-plugins", jsPlugins.filesystem()), JS_PLUGINS_PATH_SPEC);
+ context.addServlet(servletHolder("js-plugins", jsPlugins.filesystem().toString()), JS_PLUGINS_PATH_SPEC);
 
  // Set up websockets for grpc-web - depending on configuration, we can register both in case we encounter a
  // client using "vanilla"
@@ -380,12 +372,12 @@ public void onClosed(Connection connection) {
  return serverConnector;
  }
 
- private static ServletHolder servletHolder(String name, URI filesystemUri) {
+ private static ServletHolder servletHolder(String name, String resources) {
  final ServletHolder jsPlugins = new ServletHolder(name, DefaultServlet.class);
  // Note, the URI needs explicitly be parseable as a directory URL ending in "!/", a requirement of the jetty
  // resource creation implementation, see
  // org.eclipse.jetty.util.resource.Resource.newResource(java.lang.String, boolean)
- jsPlugins.setInitParameter("resourceBase", filesystemUri.toString());
+ jsPlugins.setInitParameter("resourceBase", resources);
  jsPlugins.setInitParameter("pathInfoOnly", "true");
  jsPlugins.setInitParameter("dirAllowed", "false");
  jsPlugins.setAsyncSupported(true);