code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.grid.gridui;
  
  import java.net.MalformedURLException;
  import java.net.URL;
  import org.openqa.selenium.grid.server.Server;
  
  class Urls {
  
    private Urls() {
      // Utility class
    }
  
    public static String whereIs(Server<?> server, String url) {
      return getRelativeUrl(server.getUrl(), url).toString();
    }
  
    public static URL getRelativeUrl(URL base, String relativePath) {
      if (relativePath.isEmpty() || "/".equals(relativePath)) {
        return base;
      }
  
      try {
        String path = base.getPath();
        if (!path.endsWith("/")) {
          path = path + "/";
        }
  
        if (relativePath.startsWith("/")) {
          path = path + relativePath.substring(1);
        } else {
          path = path + relativePath;
        }
  
        return new URL(base, path);
      } catch (MalformedURLException e) {
        throw new RuntimeException(e);
      }
    }
  }
  