gt:         if (connectionId == null)
context: /*
   * Copyright (c) 2002, 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package javax.management.remote.rmi;
  
  import java.io.IOException;
  import java.io.ObjectInputFilter;
  import java.rmi.NoSuchObjectException;
  import java.rmi.Remote;
  import java.rmi.RemoteException;
  import java.rmi.server.RMIClientSocketFactory;
  import java.rmi.server.RMIServerSocketFactory;
  import java.rmi.server.UnicastRemoteObject;
  import java.rmi.server.RemoteObject;
  import java.util.Map;
  import java.util.Collections;
  import javax.security.auth.Subject;
  
  import com.sun.jmx.remote.internal.rmi.RMIExporter;
  import com.sun.jmx.remote.util.EnvHelp;
  import java.util.Arrays;
  import java.util.Set;
  import java.util.stream.Collectors;
  import sun.reflect.misc.ReflectUtil;
  import sun.rmi.server.UnicastServerRef;
  import sun.rmi.server.UnicastServerRef2;
  import sun.rmi.transport.LiveRef;
  
  /**
   * <p>An {@link RMIServer} object that is exported through JRMP and that
   * creates client connections as RMI objects exported through JRMP.
   * User code does not usually reference this class directly.</p>
   *
   * @see RMIServerImpl
   *
   * @since 1.5
   */
  public class RMIJRMPServerImpl extends RMIServerImpl {
  
      /**
       * <p>Creates a new {@link RMIServer} object that will be exported
       * on the given port using the given socket factories.</p>
       *
       * @param port the port on which this object and the {@link
       * RMIConnectionImpl} objects it creates will be exported.  Can be
       * zero, to indicate any available port.
       *
       * @param csf the client socket factory for the created RMI
       * objects.  Can be null.
       *
       * @param ssf the server socket factory for the created RMI
       * objects.  Can be null.
       *
       * @param env the environment map.  Can be null.
       *
       * @exception IOException if the {@link RMIServer} object
       * cannot be created.
       *
       * @exception IllegalArgumentException if <code>port</code> is
       * negative.
       */
      public RMIJRMPServerImpl(int port,
                               RMIClientSocketFactory csf,
                               RMIServerSocketFactory ssf,
                               Map<String,?> env)
              throws IOException {
  
          super(env);
  
          if (port < 0)
              throw new IllegalArgumentException("Negative port: " + port);
  
          this.port = port;
          this.csf = csf;
          this.ssf = ssf;
          this.env = (env == null) ? Collections.<String, Object>emptyMap() : env;
  
          // This attribute was represented by RMIConnectorServer.CREDENTIALS_TYPES.
          // This attribute is superceded by
          // RMIConnectorServer.CREDENTIALS_FILTER_PATTERN.
          // Retaining this for backward compatibility.
          String[] credentialsTypes
                  = (String[]) this.env.get("jmx.remote.rmi.server.credential.types");
  
          String credentialsFilter
                  = (String) this.env.get(RMIConnectorServer.CREDENTIALS_FILTER_PATTERN);
  
          // It is impossible for both attributes to be specified
          if(credentialsTypes != null && credentialsFilter != null)
              throw new IllegalArgumentException("Cannot specify both \""
                      + "jmx.remote.rmi.server.credential.types" + "\" and \""
             + RMIConnectorServer.CREDENTIALS_FILTER_PATTERN + "\"");
          else if(credentialsFilter != null){
              cFilter = ObjectInputFilter.Config.createFilter(credentialsFilter);
              allowedTypes = null;
          }
          else if (credentialsTypes != null) {
              allowedTypes = Arrays.stream(credentialsTypes).filter(
                      s -> s!= null).collect(Collectors.toSet());
              allowedTypes.stream().forEach(ReflectUtil::checkPackageAccess);
              cFilter = this::newClientCheckInput;
          } else {
              allowedTypes = null;
              cFilter = null;
          }
  
          String userJmxFilter =
                  (String) this.env.get(RMIConnectorServer.SERIAL_FILTER_PATTERN);
          if(userJmxFilter != null && !userJmxFilter.isEmpty())
              jmxRmiFilter = ObjectInputFilter.Config.createFilter(userJmxFilter);
          else
              jmxRmiFilter = null;
      }
  
      protected void export() throws IOException {
          export(this, cFilter);
      }
  
      private void export(Remote obj, ObjectInputFilter typeFilter) throws RemoteException {
          final RMIExporter exporter =
              (RMIExporter) env.get(RMIExporter.EXPORTER_ATTRIBUTE);
          final boolean daemon = EnvHelp.isServerDaemon(env);
  
          if (daemon && exporter != null) {
              throw new IllegalArgumentException("If "+EnvHelp.JMX_SERVER_DAEMON+
                      " is specified as true, "+RMIExporter.EXPORTER_ATTRIBUTE+
                      " cannot be used to specify an exporter!");
          }
  
          if (exporter != null) {
              exporter.exportObject(obj, port, csf, ssf, typeFilter);
          } else {
              if (csf == null && ssf == null) {
                  new UnicastServerRef(new LiveRef(port), typeFilter).exportObject(obj, null, daemon);
              } else {
                  new UnicastServerRef2(port, csf, ssf, typeFilter).exportObject(obj, null, daemon);
              }
          }
      }
  
      private void unexport(Remote obj, boolean force)
              throws NoSuchObjectException {
          RMIExporter exporter =
              (RMIExporter) env.get(RMIExporter.EXPORTER_ATTRIBUTE);
          if (exporter == null)
              UnicastRemoteObject.unexportObject(obj, force);
          else
              exporter.unexportObject(obj, force);
      }
  
      protected String getProtocol() {
          return "rmi";
      }
  
      /**
       * <p>Returns a serializable stub for this {@link RMIServer} object.</p>
       *
       * @return a serializable stub.
       *
       * @exception IOException if the stub cannot be obtained - e.g the
       *            RMIJRMPServerImpl has not been exported yet.
       */
      public Remote toStub() throws IOException {
          return RemoteObject.toStub(this);
      }
  
      /**
       * <p>Creates a new client connection as an RMI object exported
       * through JRMP. The port and socket factories for the new
       * {@link RMIConnection} object are the ones supplied
       * to the <code>RMIJRMPServerImpl</code> constructor.</p>
       *
       * @param connectionId the ID of the new connection. Every
       * connection opened by this connector server will have a
       * different id.  The behavior is unspecified if this parameter is
       * null.
       *
       * @param subject the authenticated subject.  Can be null.
       *
       * @return the newly-created <code>RMIConnection</code>.
       *
       * @exception IOException if the new {@link RMIConnection}
       * object cannot be created or exported.
       */
      protected RMIConnection makeClient(String connectionId, Subject subject)
              throws IOException {
  
  