1 /*
   2  * Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.net;
  27 
  28 import java.io.IOException;
  29 import java.io.InputStream;
  30 import java.net.spi.URLStreamHandlerProvider;
  31 import java.security.AccessController;
  32 import java.security.PrivilegedAction;
  33 import java.util.Hashtable;
  34 import java.io.InvalidObjectException;
  35 import java.io.ObjectStreamException;
  36 import java.io.ObjectStreamField;
  37 import java.io.ObjectInputStream.GetField;
  38 import java.util.Iterator;
  39 import java.util.Locale;
  40 import java.util.NoSuchElementException;
  41 import java.util.ServiceConfigurationError;
  42 import java.util.ServiceLoader;
  43 
  44 import jdk.internal.misc.JavaNetURLAccess;
  45 import jdk.internal.misc.SharedSecrets;
  46 import sun.security.util.SecurityConstants;
  47 import sun.security.action.GetPropertyAction;
  48 
  49 /**
  50  * Class {@code URL} represents a Uniform Resource
  51  * Locator, a pointer to a "resource" on the World
  52  * Wide Web. A resource can be something as simple as a file or a
  53  * directory, or it can be a reference to a more complicated object,
  54  * such as a query to a database or to a search engine. More
  55  * information on the types of URLs and their formats can be found at:
  56  * <a href=
  57  * "http://web.archive.org/web/20051219043731/http://archive.ncsa.uiuc.edu/SDG/Software/Mosaic/Demo/url-primer.html">
  58  * <i>Types of URL</i></a>
  59  * <p>
  60  * In general, a URL can be broken into several parts. Consider the
  61  * following example:
  62  * <blockquote><pre>
  63  *     http://www.example.com/docs/resource1.html
  64  * </pre></blockquote>
  65  * <p>
  66  * The URL above indicates that the protocol to use is
  67  * {@code http} (HyperText Transfer Protocol) and that the
  68  * information resides on a host machine named
  69  * {@code www.example.com}. The information on that host
  70  * machine is named {@code /docs/resource1.html}. The exact
  71  * meaning of this name on the host machine is both protocol
  72  * dependent and host dependent. The information normally resides in
  73  * a file, but it could be generated on the fly. This component of
  74  * the URL is called the <i>path</i> component.
  75  * <p>
  76  * A URL can optionally specify a "port", which is the
  77  * port number to which the TCP connection is made on the remote host
  78  * machine. If the port is not specified, the default port for
  79  * the protocol is used instead. For example, the default port for
  80  * {@code http} is {@code 80}. An alternative port could be
  81  * specified as:
  82  * <blockquote><pre>
  83  *     http://www.example.com:1080/docs/resource1.html
  84  * </pre></blockquote>
  85  * <p>
  86  * The syntax of {@code URL} is defined by  <a
  87  * href="http://www.ietf.org/rfc/rfc2396.txt"><i>RFC&nbsp;2396: Uniform
  88  * Resource Identifiers (URI): Generic Syntax</i></a>, amended by <a
  89  * href="http://www.ietf.org/rfc/rfc2732.txt"><i>RFC&nbsp;2732: Format for
  90  * Literal IPv6 Addresses in URLs</i></a>. The Literal IPv6 address format
  91  * also supports scope_ids. The syntax and usage of scope_ids is described
  92  * <a href="Inet6Address.html#scoped">here</a>.
  93  * <p>
  94  * A URL may have appended to it a "fragment", also known
  95  * as a "ref" or a "reference". The fragment is indicated by the sharp
  96  * sign character "#" followed by more characters. For example,
  97  * <blockquote><pre>
  98  *     http://java.sun.com/index.html#chapter1
  99  * </pre></blockquote>
 100  * <p>
 101  * This fragment is not technically part of the URL. Rather, it
 102  * indicates that after the specified resource is retrieved, the
 103  * application is specifically interested in that part of the
 104  * document that has the tag {@code chapter1} attached to it. The
 105  * meaning of a tag is resource specific.
 106  * <p>
 107  * An application can also specify a "relative URL",
 108  * which contains only enough information to reach the resource
 109  * relative to another URL. Relative URLs are frequently used within
 110  * HTML pages. For example, if the contents of the URL:
 111  * <blockquote><pre>
 112  *     http://java.sun.com/index.html
 113  * </pre></blockquote>
 114  * contained within it the relative URL:
 115  * <blockquote><pre>
 116  *     FAQ.html
 117  * </pre></blockquote>
 118  * it would be a shorthand for:
 119  * <blockquote><pre>
 120  *     http://java.sun.com/FAQ.html
 121  * </pre></blockquote>
 122  * <p>
 123  * The relative URL need not specify all the components of a URL. If
 124  * the protocol, host name, or port number is missing, the value is
 125  * inherited from the fully specified URL. The file component must be
 126  * specified. The optional fragment is not inherited.
 127  * <p>
 128  * The URL class does not itself encode or decode any URL components
 129  * according to the escaping mechanism defined in RFC2396. It is the
 130  * responsibility of the caller to encode any fields, which need to be
 131  * escaped prior to calling URL, and also to decode any escaped fields,
 132  * that are returned from URL. Furthermore, because URL has no knowledge
 133  * of URL escaping, it does not recognise equivalence between the encoded
 134  * or decoded form of the same URL. For example, the two URLs:<br>
 135  * <pre>    http://foo.com/hello world/ and http://foo.com/hello%20world</pre>
 136  * would be considered not equal to each other.
 137  * <p>
 138  * Note, the {@link java.net.URI} class does perform escaping of its
 139  * component fields in certain circumstances. The recommended way
 140  * to manage the encoding and decoding of URLs is to use {@link java.net.URI},
 141  * and to convert between these two classes using {@link #toURI()} and
 142  * {@link URI#toURL()}.
 143  * <p>
 144  * The {@link URLEncoder} and {@link URLDecoder} classes can also be
 145  * used, but only for HTML form encoding, which is not the same
 146  * as the encoding scheme defined in RFC2396.
 147  *
 148  * @author  James Gosling
 149  * @since 1.0
 150  */
 151 public final class URL implements java.io.Serializable {
 152 
 153     static final String BUILTIN_HANDLERS_PREFIX = "sun.net.www.protocol";
 154     static final long serialVersionUID = -7627629688361524110L;
 155 
 156     /**
 157      * The property which specifies the package prefix list to be scanned
 158      * for protocol handlers.  The value of this property (if any) should
 159      * be a vertical bar delimited list of package names to search through
 160      * for a protocol handler to load.  The policy of this class is that
 161      * all protocol handlers will be in a class called <protocolname>.Handler,
 162      * and each package in the list is examined in turn for a matching
 163      * handler.  If none are found (or the property is not specified), the
 164      * default package prefix, sun.net.www.protocol, is used.  The search
 165      * proceeds from the first package in the list to the last and stops
 166      * when a match is found.
 167      */
 168     private static final String protocolPathProp = "java.protocol.handler.pkgs";
 169 
 170     /**
 171      * The protocol to use (ftp, http, nntp, ... etc.) .
 172      * @serial
 173      */
 174     private String protocol;
 175 
 176     /**
 177      * The host name to connect to.
 178      * @serial
 179      */
 180     private String host;
 181 
 182     /**
 183      * The protocol port to connect to.
 184      * @serial
 185      */
 186     private int port = -1;
 187 
 188     /**
 189      * The specified file name on that host. {@code file} is
 190      * defined as {@code path[?query]}
 191      * @serial
 192      */
 193     private String file;
 194 
 195     /**
 196      * The query part of this URL.
 197      */
 198     private transient String query;
 199 
 200     /**
 201      * The authority part of this URL.
 202      * @serial
 203      */
 204     private String authority;
 205 
 206     /**
 207      * The path part of this URL.
 208      */
 209     private transient String path;
 210 
 211     /**
 212      * The userinfo part of this URL.
 213      */
 214     private transient String userInfo;
 215 
 216     /**
 217      * # reference.
 218      * @serial
 219      */
 220     private String ref;
 221 
 222     /**
 223      * The host's IP address, used in equals and hashCode.
 224      * Computed on demand. An uninitialized or unknown hostAddress is null.
 225      */
 226     transient InetAddress hostAddress;
 227 
 228     /**
 229      * The URLStreamHandler for this URL.
 230      */
 231     transient URLStreamHandler handler;
 232 
 233     /* Our hash code.
 234      * @serial
 235      */
 236     private int hashCode = -1;
 237 
 238     private transient UrlDeserializedState tempState;
 239 
 240     /**
 241      * Creates a {@code URL} object from the specified
 242      * {@code protocol}, {@code host}, {@code port}
 243      * number, and {@code file}.<p>
 244      *
 245      * {@code host} can be expressed as a host name or a literal
 246      * IP address. If IPv6 literal address is used, it should be
 247      * enclosed in square brackets ({@code '['} and {@code ']'}), as
 248      * specified by <a
 249      * href="http://www.ietf.org/rfc/rfc2732.txt">RFC&nbsp;2732</a>;
 250      * However, the literal IPv6 address format defined in <a
 251      * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC&nbsp;2373: IP
 252      * Version 6 Addressing Architecture</i></a> is also accepted.<p>
 253      *
 254      * Specifying a {@code port} number of {@code -1}
 255      * indicates that the URL should use the default port for the
 256      * protocol.<p>
 257      *
 258      * If this is the first URL object being created with the specified
 259      * protocol, a <i>stream protocol handler</i> object, an instance of
 260      * class {@code URLStreamHandler}, is created for that protocol:
 261      * <ol>
 262      * <li>If the application has previously set up an instance of
 263      *     {@code URLStreamHandlerFactory} as the stream handler factory,
 264      *     then the {@code createURLStreamHandler} method of that instance
 265      *     is called with the protocol string as an argument to create the
 266      *     stream protocol handler.
 267      * <li>If no {@code URLStreamHandlerFactory} has yet been set up,
 268      *     or if the factory's {@code createURLStreamHandler} method
 269      *     returns {@code null}, then the {@linkplain java.util.ServiceLoader
 270      *     ServiceLoader} mechanism is used to locate {@linkplain
 271      *     java.net.spi.URLStreamHandlerProvider URLStreamHandlerProvider}
 272      *     implementations using the system class
 273      *     loader. The order that providers are located is implementation
 274      *     specific, and an implementation is free to cache the located
 275      *     providers. A {@linkplain java.util.ServiceConfigurationError
 276      *     ServiceConfigurationError}, {@code Error} or {@code RuntimeException}
 277      *     thrown from the {@code createURLStreamHandler}, if encountered, will
 278      *     be propagated to the calling thread. The {@code
 279      *     createURLStreamHandler} method of each provider, if instantiated, is
 280      *     invoked, with the protocol string, until a provider returns non-null,
 281      *     or all providers have been exhausted.
 282      * <li>If the previous step fails to find a protocol handler, the
 283      *     constructor reads the value of the system property:
 284      *     <blockquote>{@code
 285      *         java.protocol.handler.pkgs
 286      *     }</blockquote>
 287      *     If the value of that system property is not {@code null},
 288      *     it is interpreted as a list of packages separated by a vertical
 289      *     slash character '{@code |}'. The constructor tries to load
 290      *     the class named:
 291      *     <blockquote>{@code
 292      *         <package>.<protocol>.Handler
 293      *     }</blockquote>
 294      *     where {@code <package>} is replaced by the name of the package
 295      *     and {@code <protocol>} is replaced by the name of the protocol.
 296      *     If this class does not exist, or if the class exists but it is not
 297      *     a subclass of {@code URLStreamHandler}, then the next package
 298      *     in the list is tried.
 299      * <li>If the previous step fails to find a protocol handler, then the
 300      *     constructor tries to load a built-in protocol handler.
 301      *     If this class does not exist, or if the class exists but it is not a
 302      *     subclass of {@code URLStreamHandler}, then a
 303      *     {@code MalformedURLException} is thrown.
 304      * </ol>
 305      *
 306      * <p>Protocol handlers for the following protocols are guaranteed
 307      * to exist on the search path :-
 308      * <blockquote><pre>
 309      *     http, https, file, and jar
 310      * </pre></blockquote>
 311      * Protocol handlers for additional protocols may also be  available.
 312      * Some protocol handlers, for example those used for loading platform
 313      * classes or classes on the class path, may not be overridden. The details
 314      * of such restrictions, and when those restrictions apply (during
 315      * initialization of the runtime for example), are implementation specific
 316      * and therefore not specified
 317      *
 318      * <p>No validation of the inputs is performed by this constructor.
 319      *
 320      * @param      protocol   the name of the protocol to use.
 321      * @param      host       the name of the host.
 322      * @param      port       the port number on the host.
 323      * @param      file       the file on the host
 324      * @exception  MalformedURLException  if an unknown protocol or the port
 325      *                  is a negative number other than -1
 326      * @see        java.lang.System#getProperty(java.lang.String)
 327      * @see        java.net.URL#setURLStreamHandlerFactory(
 328      *                  java.net.URLStreamHandlerFactory)
 329      * @see        java.net.URLStreamHandler
 330      * @see        java.net.URLStreamHandlerFactory#createURLStreamHandler(
 331      *                  java.lang.String)
 332      */
 333     public URL(String protocol, String host, int port, String file)
 334         throws MalformedURLException
 335     {
 336         this(protocol, host, port, file, null);
 337     }
 338 
 339     /**
 340      * Creates a URL from the specified {@code protocol}
 341      * name, {@code host} name, and {@code file} name. The
 342      * default port for the specified protocol is used.
 343      * <p>
 344      * This constructor is equivalent to the four-argument
 345      * constructor with the only difference of using the
 346      * default port for the specified protocol.
 347      *
 348      * No validation of the inputs is performed by this constructor.
 349      *
 350      * @param      protocol   the name of the protocol to use.
 351      * @param      host       the name of the host.
 352      * @param      file       the file on the host.
 353      * @exception  MalformedURLException  if an unknown protocol is specified.
 354      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 355      *                  int, java.lang.String)
 356      */
 357     public URL(String protocol, String host, String file)
 358             throws MalformedURLException {
 359         this(protocol, host, -1, file);
 360     }
 361 
 362     /**
 363      * Creates a {@code URL} object from the specified
 364      * {@code protocol}, {@code host}, {@code port}
 365      * number, {@code file}, and {@code handler}. Specifying
 366      * a {@code port} number of {@code -1} indicates that
 367      * the URL should use the default port for the protocol. Specifying
 368      * a {@code handler} of {@code null} indicates that the URL
 369      * should use a default stream handler for the protocol, as outlined
 370      * for:
 371      *     java.net.URL#URL(java.lang.String, java.lang.String, int,
 372      *                      java.lang.String)
 373      *
 374      * <p>If the handler is not null and there is a security manager,
 375      * the security manager's {@code checkPermission}
 376      * method is called with a
 377      * {@code NetPermission("specifyStreamHandler")} permission.
 378      * This may result in a SecurityException.
 379      *
 380      * No validation of the inputs is performed by this constructor.
 381      *
 382      * @param      protocol   the name of the protocol to use.
 383      * @param      host       the name of the host.
 384      * @param      port       the port number on the host.
 385      * @param      file       the file on the host
 386      * @param      handler    the stream handler for the URL.
 387      * @exception  MalformedURLException  if an unknown protocol or the port
 388                         is a negative number other than -1
 389      * @exception  SecurityException
 390      *        if a security manager exists and its
 391      *        {@code checkPermission} method doesn't allow
 392      *        specifying a stream handler explicitly.
 393      * @see        java.lang.System#getProperty(java.lang.String)
 394      * @see        java.net.URL#setURLStreamHandlerFactory(
 395      *                  java.net.URLStreamHandlerFactory)
 396      * @see        java.net.URLStreamHandler
 397      * @see        java.net.URLStreamHandlerFactory#createURLStreamHandler(
 398      *                  java.lang.String)
 399      * @see        SecurityManager#checkPermission
 400      * @see        java.net.NetPermission
 401      */
 402     public URL(String protocol, String host, int port, String file,
 403                URLStreamHandler handler) throws MalformedURLException {
 404         if (handler != null) {
 405             SecurityManager sm = System.getSecurityManager();
 406             if (sm != null) {
 407                 // check for permission to specify a handler
 408                 checkSpecifyHandler(sm);
 409             }
 410         }
 411 
 412         protocol = toLowerCase(protocol);
 413         this.protocol = protocol;
 414         if (host != null) {
 415 
 416             /**
 417              * if host is a literal IPv6 address,
 418              * we will make it conform to RFC 2732
 419              */
 420             if (host.indexOf(':') >= 0 && !host.startsWith("[")) {
 421                 host = "["+host+"]";
 422             }
 423             this.host = host;
 424 
 425             if (port < -1) {
 426                 throw new MalformedURLException("Invalid port number :" +
 427                                                     port);
 428             }
 429             this.port = port;
 430             authority = (port == -1) ? host : host + ":" + port;
 431         }
 432 
 433         int index = file.indexOf('#');
 434         this.ref = index < 0 ? null : file.substring(index + 1);
 435         file = index < 0 ? file : file.substring(0, index);
 436         int q = file.lastIndexOf('?');
 437         if (q != -1) {
 438             this.query = file.substring(q + 1);
 439             this.path = file.substring(0, q);
 440             this.file = path + "?" + query;
 441         } else {
 442             this.path = file;
 443             this.file = path;
 444         }
 445 
 446         // Note: we don't do validation of the URL here. Too risky to change
 447         // right now, but worth considering for future reference. -br
 448         if (handler == null &&
 449             (handler = getURLStreamHandler(protocol)) == null) {
 450             throw new MalformedURLException("unknown protocol: " + protocol);
 451         }
 452         this.handler = handler;
 453     }
 454 
 455     /**
 456      * Creates a {@code URL} object from the {@code String}
 457      * representation.
 458      * <p>
 459      * This constructor is equivalent to a call to the two-argument
 460      * constructor with a {@code null} first argument.
 461      *
 462      * @param      spec   the {@code String} to parse as a URL.
 463      * @exception  MalformedURLException  if no protocol is specified, or an
 464      *               unknown protocol is found, or {@code spec} is {@code null},
 465      *               or the parsed URL fails to comply with the specific syntax
 466      *               of the associated protocol.
 467      * @see        java.net.URL#URL(java.net.URL, java.lang.String)
 468      */
 469     public URL(String spec) throws MalformedURLException {
 470         this(null, spec);
 471     }
 472 
 473     /**
 474      * Creates a URL by parsing the given spec within a specified context.
 475      *
 476      * The new URL is created from the given context URL and the spec
 477      * argument as described in
 478      * RFC2396 &quot;Uniform Resource Identifiers : Generic * Syntax&quot; :
 479      * <blockquote><pre>
 480      *          &lt;scheme&gt;://&lt;authority&gt;&lt;path&gt;?&lt;query&gt;#&lt;fragment&gt;
 481      * </pre></blockquote>
 482      * The reference is parsed into the scheme, authority, path, query and
 483      * fragment parts. If the path component is empty and the scheme,
 484      * authority, and query components are undefined, then the new URL is a
 485      * reference to the current document. Otherwise, the fragment and query
 486      * parts present in the spec are used in the new URL.
 487      * <p>
 488      * If the scheme component is defined in the given spec and does not match
 489      * the scheme of the context, then the new URL is created as an absolute
 490      * URL based on the spec alone. Otherwise the scheme component is inherited
 491      * from the context URL.
 492      * <p>
 493      * If the authority component is present in the spec then the spec is
 494      * treated as absolute and the spec authority and path will replace the
 495      * context authority and path. If the authority component is absent in the
 496      * spec then the authority of the new URL will be inherited from the
 497      * context.
 498      * <p>
 499      * If the spec's path component begins with a slash character
 500      * &quot;/&quot; then the
 501      * path is treated as absolute and the spec path replaces the context path.
 502      * <p>
 503      * Otherwise, the path is treated as a relative path and is appended to the
 504      * context path, as described in RFC2396. Also, in this case,
 505      * the path is canonicalized through the removal of directory
 506      * changes made by occurrences of &quot;..&quot; and &quot;.&quot;.
 507      * <p>
 508      * For a more detailed description of URL parsing, refer to RFC2396.
 509      *
 510      * @param      context   the context in which to parse the specification.
 511      * @param      spec      the {@code String} to parse as a URL.
 512      * @exception  MalformedURLException  if no protocol is specified, or an
 513      *               unknown protocol is found, or {@code spec} is {@code null},
 514      *               or the parsed URL fails to comply with the specific syntax
 515      *               of the associated protocol.
 516      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 517      *                  int, java.lang.String)
 518      * @see        java.net.URLStreamHandler
 519      * @see        java.net.URLStreamHandler#parseURL(java.net.URL,
 520      *                  java.lang.String, int, int)
 521      */
 522     public URL(URL context, String spec) throws MalformedURLException {
 523         this(context, spec, null);
 524     }
 525 
 526     /**
 527      * Creates a URL by parsing the given spec with the specified handler
 528      * within a specified context. If the handler is null, the parsing
 529      * occurs as with the two argument constructor.
 530      *
 531      * @param      context   the context in which to parse the specification.
 532      * @param      spec      the {@code String} to parse as a URL.
 533      * @param      handler   the stream handler for the URL.
 534      * @exception  MalformedURLException  if no protocol is specified, or an
 535      *               unknown protocol is found, or {@code spec} is {@code null},
 536      *               or the parsed URL fails to comply with the specific syntax
 537      *               of the associated protocol.
 538      * @exception  SecurityException
 539      *        if a security manager exists and its
 540      *        {@code checkPermission} method doesn't allow
 541      *        specifying a stream handler.
 542      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 543      *                  int, java.lang.String)
 544      * @see        java.net.URLStreamHandler
 545      * @see        java.net.URLStreamHandler#parseURL(java.net.URL,
 546      *                  java.lang.String, int, int)
 547      */
 548     public URL(URL context, String spec, URLStreamHandler handler)
 549         throws MalformedURLException
 550     {
 551         String original = spec;
 552         int i, limit, c;
 553         int start = 0;
 554         String newProtocol = null;
 555         boolean aRef=false;
 556         boolean isRelative = false;
 557 
 558         // Check for permission to specify a handler
 559         if (handler != null) {
 560             SecurityManager sm = System.getSecurityManager();
 561             if (sm != null) {
 562                 checkSpecifyHandler(sm);
 563             }
 564         }
 565 
 566         try {
 567             limit = spec.length();
 568             while ((limit > 0) && (spec.charAt(limit - 1) <= ' ')) {
 569                 limit--;        //eliminate trailing whitespace
 570             }
 571             while ((start < limit) && (spec.charAt(start) <= ' ')) {
 572                 start++;        // eliminate leading whitespace
 573             }
 574 
 575             if (spec.regionMatches(true, start, "url:", 0, 4)) {
 576                 start += 4;
 577             }
 578             if (start < spec.length() && spec.charAt(start) == '#') {
 579                 /* we're assuming this is a ref relative to the context URL.
 580                  * This means protocols cannot start w/ '#', but we must parse
 581                  * ref URL's like: "hello:there" w/ a ':' in them.
 582                  */
 583                 aRef=true;
 584             }
 585             for (i = start ; !aRef && (i < limit) &&
 586                      ((c = spec.charAt(i)) != '/') ; i++) {
 587                 if (c == ':') {
 588                     String s = toLowerCase(spec.substring(start, i));
 589                     if (isValidProtocol(s)) {
 590                         newProtocol = s;
 591                         start = i + 1;
 592                     }
 593                     break;
 594                 }
 595             }
 596 
 597             // Only use our context if the protocols match.
 598             protocol = newProtocol;
 599             if ((context != null) && ((newProtocol == null) ||
 600                             newProtocol.equalsIgnoreCase(context.protocol))) {
 601                 // inherit the protocol handler from the context
 602                 // if not specified to the constructor
 603                 if (handler == null) {
 604                     handler = context.handler;
 605                 }
 606 
 607                 // If the context is a hierarchical URL scheme and the spec
 608                 // contains a matching scheme then maintain backwards
 609                 // compatibility and treat it as if the spec didn't contain
 610                 // the scheme; see 5.2.3 of RFC2396
 611                 if (context.path != null && context.path.startsWith("/"))
 612                     newProtocol = null;
 613 
 614                 if (newProtocol == null) {
 615                     protocol = context.protocol;
 616                     authority = context.authority;
 617                     userInfo = context.userInfo;
 618                     host = context.host;
 619                     port = context.port;
 620                     file = context.file;
 621                     path = context.path;
 622                     isRelative = true;
 623                 }
 624             }
 625 
 626             if (protocol == null) {
 627                 throw new MalformedURLException("no protocol: "+original);
 628             }
 629 
 630             // Get the protocol handler if not specified or the protocol
 631             // of the context could not be used
 632             if (handler == null &&
 633                 (handler = getURLStreamHandler(protocol)) == null) {
 634                 throw new MalformedURLException("unknown protocol: "+protocol);
 635             }
 636 
 637             this.handler = handler;
 638 
 639             i = spec.indexOf('#', start);
 640             if (i >= 0) {
 641                 ref = spec.substring(i + 1, limit);
 642                 limit = i;
 643             }
 644 
 645             /*
 646              * Handle special case inheritance of query and fragment
 647              * implied by RFC2396 section 5.2.2.
 648              */
 649             if (isRelative && start == limit) {
 650                 query = context.query;
 651                 if (ref == null) {
 652                     ref = context.ref;
 653                 }
 654             }
 655 
 656             handler.parseURL(this, spec, start, limit);
 657 
 658         } catch(MalformedURLException e) {
 659             throw e;
 660         } catch(Exception e) {
 661             MalformedURLException exception = new MalformedURLException(e.getMessage());
 662             exception.initCause(e);
 663             throw exception;
 664         }
 665     }
 666 
 667     /**
 668      * Creates a URL from a URI, as if by invoking {@code uri.toURL()}.
 669      *
 670      * @see java.net.URI#toURL()
 671      */
 672     static URL fromURI(URI uri) throws MalformedURLException {
 673         if (!uri.isAbsolute()) {
 674             throw new IllegalArgumentException("URI is not absolute");
 675         }
 676         String protocol = uri.getScheme();
 677 
 678         // In general we need to go via Handler.parseURL, but for the jrt
 679         // protocol we enforce that the Handler is not overrideable and can
 680         // optimize URI to URL conversion.
 681         //
 682         // Case-sensitive comparison for performance; malformed protocols will
 683         // be handled correctly by the slow path.
 684         if (protocol.equals("jrt") && !uri.isOpaque()
 685                 && uri.getRawFragment() == null) {
 686 
 687             String query = uri.getRawQuery();
 688             String path = uri.getRawPath();
 689             String file = (query == null) ? path : path + "?" + query;
 690 
 691             // URL represent undefined host as empty string while URI use null
 692             String host = uri.getHost();
 693             if (host == null) {
 694                 host = "";
 695             }
 696 
 697             int port = uri.getPort();
 698 
 699             return new URL("jrt", host, port, file, null);
 700         } else {
 701             return new URL((URL)null, uri.toString(), null);
 702         }
 703     }
 704 
 705     /*
 706      * Returns true if specified string is a valid protocol name.
 707      */
 708     private boolean isValidProtocol(String protocol) {
 709         int len = protocol.length();
 710         if (len < 1)
 711             return false;
 712         char c = protocol.charAt(0);
 713         if (!Character.isLetter(c))
 714             return false;
 715         for (int i = 1; i < len; i++) {
 716             c = protocol.charAt(i);
 717             if (!Character.isLetterOrDigit(c) && c != '.' && c != '+' &&
 718                 c != '-') {
 719                 return false;
 720             }
 721         }
 722         return true;
 723     }
 724 
 725     /*
 726      * Checks for permission to specify a stream handler.
 727      */
 728     private void checkSpecifyHandler(SecurityManager sm) {
 729         sm.checkPermission(SecurityConstants.SPECIFY_HANDLER_PERMISSION);
 730     }
 731 
 732     /**
 733      * Sets the fields of the URL. This is not a public method so that
 734      * only URLStreamHandlers can modify URL fields. URLs are
 735      * otherwise constant.
 736      *
 737      * @param protocol the name of the protocol to use
 738      * @param host the name of the host
 739        @param port the port number on the host
 740      * @param file the file on the host
 741      * @param ref the internal reference in the URL
 742      */
 743     void set(String protocol, String host, int port,
 744              String file, String ref) {
 745         synchronized (this) {
 746             this.protocol = protocol;
 747             this.host = host;
 748             authority = port == -1 ? host : host + ":" + port;
 749             this.port = port;
 750             this.file = file;
 751             this.ref = ref;
 752             /* This is very important. We must recompute this after the
 753              * URL has been changed. */
 754             hashCode = -1;
 755             hostAddress = null;
 756             int q = file.lastIndexOf('?');
 757             if (q != -1) {
 758                 query = file.substring(q+1);
 759                 path = file.substring(0, q);
 760             } else
 761                 path = file;
 762         }
 763     }
 764 
 765     /**
 766      * Sets the specified 8 fields of the URL. This is not a public method so
 767      * that only URLStreamHandlers can modify URL fields. URLs are otherwise
 768      * constant.
 769      *
 770      * @param protocol the name of the protocol to use
 771      * @param host the name of the host
 772      * @param port the port number on the host
 773      * @param authority the authority part for the url
 774      * @param userInfo the username and password
 775      * @param path the file on the host
 776      * @param ref the internal reference in the URL
 777      * @param query the query part of this URL
 778      * @since 1.3
 779      */
 780     void set(String protocol, String host, int port,
 781              String authority, String userInfo, String path,
 782              String query, String ref) {
 783         synchronized (this) {
 784             this.protocol = protocol;
 785             this.host = host;
 786             this.port = port;
 787             this.file = query == null ? path : path + "?" + query;
 788             this.userInfo = userInfo;
 789             this.path = path;
 790             this.ref = ref;
 791             /* This is very important. We must recompute this after the
 792              * URL has been changed. */
 793             hashCode = -1;
 794             hostAddress = null;
 795             this.query = query;
 796             this.authority = authority;
 797         }
 798     }
 799 
 800     /**
 801      * Gets the query part of this {@code URL}.
 802      *
 803      * @return  the query part of this {@code URL},
 804      * or <CODE>null</CODE> if one does not exist
 805      * @since 1.3
 806      */
 807     public String getQuery() {
 808         return query;
 809     }
 810 
 811     /**
 812      * Gets the path part of this {@code URL}.
 813      *
 814      * @return  the path part of this {@code URL}, or an
 815      * empty string if one does not exist
 816      * @since 1.3
 817      */
 818     public String getPath() {
 819         return path;
 820     }
 821 
 822     /**
 823      * Gets the userInfo part of this {@code URL}.
 824      *
 825      * @return  the userInfo part of this {@code URL}, or
 826      * <CODE>null</CODE> if one does not exist
 827      * @since 1.3
 828      */
 829     public String getUserInfo() {
 830         return userInfo;
 831     }
 832 
 833     /**
 834      * Gets the authority part of this {@code URL}.
 835      *
 836      * @return  the authority part of this {@code URL}
 837      * @since 1.3
 838      */
 839     public String getAuthority() {
 840         return authority;
 841     }
 842 
 843     /**
 844      * Gets the port number of this {@code URL}.
 845      *
 846      * @return  the port number, or -1 if the port is not set
 847      */
 848     public int getPort() {
 849         return port;
 850     }
 851 
 852     /**
 853      * Gets the default port number of the protocol associated
 854      * with this {@code URL}. If the URL scheme or the URLStreamHandler
 855      * for the URL do not define a default port number,
 856      * then -1 is returned.
 857      *
 858      * @return  the port number
 859      * @since 1.4
 860      */
 861     public int getDefaultPort() {
 862         return handler.getDefaultPort();
 863     }
 864 
 865     /**
 866      * Gets the protocol name of this {@code URL}.
 867      *
 868      * @return  the protocol of this {@code URL}.
 869      */
 870     public String getProtocol() {
 871         return protocol;
 872     }
 873 
 874     /**
 875      * Gets the host name of this {@code URL}, if applicable.
 876      * The format of the host conforms to RFC 2732, i.e. for a
 877      * literal IPv6 address, this method will return the IPv6 address
 878      * enclosed in square brackets ({@code '['} and {@code ']'}).
 879      *
 880      * @return  the host name of this {@code URL}.
 881      */
 882     public String getHost() {
 883         return host;
 884     }
 885 
 886     /**
 887      * Gets the file name of this {@code URL}.
 888      * The returned file portion will be
 889      * the same as <CODE>getPath()</CODE>, plus the concatenation of
 890      * the value of <CODE>getQuery()</CODE>, if any. If there is
 891      * no query portion, this method and <CODE>getPath()</CODE> will
 892      * return identical results.
 893      *
 894      * @return  the file name of this {@code URL},
 895      * or an empty string if one does not exist
 896      */
 897     public String getFile() {
 898         return file;
 899     }
 900 
 901     /**
 902      * Gets the anchor (also known as the "reference") of this
 903      * {@code URL}.
 904      *
 905      * @return  the anchor (also known as the "reference") of this
 906      *          {@code URL}, or <CODE>null</CODE> if one does not exist
 907      */
 908     public String getRef() {
 909         return ref;
 910     }
 911 
 912     /**
 913      * Compares this URL for equality with another object.<p>
 914      *
 915      * If the given object is not a URL then this method immediately returns
 916      * {@code false}.<p>
 917      *
 918      * Two URL objects are equal if they have the same protocol, reference
 919      * equivalent hosts, have the same port number on the host, and the same
 920      * file and fragment of the file.<p>
 921      *
 922      * Two hosts are considered equivalent if both host names can be resolved
 923      * into the same IP addresses; else if either host name can't be
 924      * resolved, the host names must be equal without regard to case; or both
 925      * host names equal to null.<p>
 926      *
 927      * Since hosts comparison requires name resolution, this operation is a
 928      * blocking operation. <p>
 929      *
 930      * Note: The defined behavior for {@code equals} is known to
 931      * be inconsistent with virtual hosting in HTTP.
 932      *
 933      * @param   obj   the URL to compare against.
 934      * @return  {@code true} if the objects are the same;
 935      *          {@code false} otherwise.
 936      */
 937     public boolean equals(Object obj) {
 938         if (!(obj instanceof URL))
 939             return false;
 940         URL u2 = (URL)obj;
 941 
 942         return handler.equals(this, u2);
 943     }
 944 
 945     /**
 946      * Creates an integer suitable for hash table indexing.<p>
 947      *
 948      * The hash code is based upon all the URL components relevant for URL
 949      * comparison. As such, this operation is a blocking operation.
 950      *
 951      * @return  a hash code for this {@code URL}.
 952      */
 953     public synchronized int hashCode() {
 954         if (hashCode != -1)
 955             return hashCode;
 956 
 957         hashCode = handler.hashCode(this);
 958         return hashCode;
 959     }
 960 
 961     /**
 962      * Compares two URLs, excluding the fragment component.<p>
 963      *
 964      * Returns {@code true} if this {@code URL} and the
 965      * {@code other} argument are equal without taking the
 966      * fragment component into consideration.
 967      *
 968      * @param   other   the {@code URL} to compare against.
 969      * @return  {@code true} if they reference the same remote object;
 970      *          {@code false} otherwise.
 971      */
 972     public boolean sameFile(URL other) {
 973         return handler.sameFile(this, other);
 974     }
 975 
 976     /**
 977      * Constructs a string representation of this {@code URL}. The
 978      * string is created by calling the {@code toExternalForm}
 979      * method of the stream protocol handler for this object.
 980      *
 981      * @return  a string representation of this object.
 982      * @see     java.net.URL#URL(java.lang.String, java.lang.String, int,
 983      *                  java.lang.String)
 984      * @see     java.net.URLStreamHandler#toExternalForm(java.net.URL)
 985      */
 986     public String toString() {
 987         return toExternalForm();
 988     }
 989 
 990     /**
 991      * Constructs a string representation of this {@code URL}. The
 992      * string is created by calling the {@code toExternalForm}
 993      * method of the stream protocol handler for this object.
 994      *
 995      * @return  a string representation of this object.
 996      * @see     java.net.URL#URL(java.lang.String, java.lang.String,
 997      *                  int, java.lang.String)
 998      * @see     java.net.URLStreamHandler#toExternalForm(java.net.URL)
 999      */
1000     public String toExternalForm() {
1001         return handler.toExternalForm(this);
1002     }
1003 
1004     /**
1005      * Returns a {@link java.net.URI} equivalent to this URL.
1006      * This method functions in the same way as {@code new URI (this.toString())}.
1007      * <p>Note, any URL instance that complies with RFC 2396 can be converted
1008      * to a URI. However, some URLs that are not strictly in compliance
1009      * can not be converted to a URI.
1010      *
1011      * @exception URISyntaxException if this URL is not formatted strictly according to
1012      *            to RFC2396 and cannot be converted to a URI.
1013      *
1014      * @return    a URI instance equivalent to this URL.
1015      * @since 1.5
1016      */
1017     public URI toURI() throws URISyntaxException {
1018         return new URI (toString());
1019     }
1020 
1021     /**
1022      * Returns a {@link java.net.URLConnection URLConnection} instance that
1023      * represents a connection to the remote object referred to by the
1024      * {@code URL}.
1025      *
1026      * <P>A new instance of {@linkplain java.net.URLConnection URLConnection} is
1027      * created every time when invoking the
1028      * {@linkplain java.net.URLStreamHandler#openConnection(URL)
1029      * URLStreamHandler.openConnection(URL)} method of the protocol handler for
1030      * this URL.</P>
1031      *
1032      * <P>It should be noted that a URLConnection instance does not establish
1033      * the actual network connection on creation. This will happen only when
1034      * calling {@linkplain java.net.URLConnection#connect() URLConnection.connect()}.</P>
1035      *
1036      * <P>If for the URL's protocol (such as HTTP or JAR), there
1037      * exists a public, specialized URLConnection subclass belonging
1038      * to one of the following packages or one of their subpackages:
1039      * java.lang, java.io, java.util, java.net, the connection
1040      * returned will be of that subclass. For example, for HTTP an
1041      * HttpURLConnection will be returned, and for JAR a
1042      * JarURLConnection will be returned.</P>
1043      *
1044      * @return     a {@link java.net.URLConnection URLConnection} linking
1045      *             to the URL.
1046      * @exception  IOException  if an I/O exception occurs.
1047      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1048      *             int, java.lang.String)
1049      */
1050     public URLConnection openConnection() throws java.io.IOException {
1051         return handler.openConnection(this);
1052     }
1053 
1054     /**
1055      * Same as {@link #openConnection()}, except that the connection will be
1056      * made through the specified proxy; Protocol handlers that do not
1057      * support proxing will ignore the proxy parameter and make a
1058      * normal connection.
1059      *
1060      * Invoking this method preempts the system's default
1061      * {@link java.net.ProxySelector ProxySelector} settings.
1062      *
1063      * @param      proxy the Proxy through which this connection
1064      *             will be made. If direct connection is desired,
1065      *             Proxy.NO_PROXY should be specified.
1066      * @return     a {@code URLConnection} to the URL.
1067      * @exception  IOException  if an I/O exception occurs.
1068      * @exception  SecurityException if a security manager is present
1069      *             and the caller doesn't have permission to connect
1070      *             to the proxy.
1071      * @exception  IllegalArgumentException will be thrown if proxy is null,
1072      *             or proxy has the wrong type
1073      * @exception  UnsupportedOperationException if the subclass that
1074      *             implements the protocol handler doesn't support
1075      *             this method.
1076      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1077      *             int, java.lang.String)
1078      * @see        java.net.URLConnection
1079      * @see        java.net.URLStreamHandler#openConnection(java.net.URL,
1080      *             java.net.Proxy)
1081      * @since      1.5
1082      */
1083     public URLConnection openConnection(Proxy proxy)
1084         throws java.io.IOException {
1085         if (proxy == null) {
1086             throw new IllegalArgumentException("proxy can not be null");
1087         }
1088 
1089         // Create a copy of Proxy as a security measure
1090         Proxy p = proxy == Proxy.NO_PROXY ? Proxy.NO_PROXY : sun.net.ApplicationProxy.create(proxy);
1091         SecurityManager sm = System.getSecurityManager();
1092         if (p.type() != Proxy.Type.DIRECT && sm != null) {
1093             InetSocketAddress epoint = (InetSocketAddress) p.address();
1094             if (epoint.isUnresolved())
1095                 sm.checkConnect(epoint.getHostName(), epoint.getPort());
1096             else
1097                 sm.checkConnect(epoint.getAddress().getHostAddress(),
1098                                 epoint.getPort());
1099         }
1100         return handler.openConnection(this, p);
1101     }
1102 
1103     /**
1104      * Opens a connection to this {@code URL} and returns an
1105      * {@code InputStream} for reading from that connection. This
1106      * method is a shorthand for:
1107      * <blockquote><pre>
1108      *     openConnection().getInputStream()
1109      * </pre></blockquote>
1110      *
1111      * @return     an input stream for reading from the URL connection.
1112      * @exception  IOException  if an I/O exception occurs.
1113      * @see        java.net.URL#openConnection()
1114      * @see        java.net.URLConnection#getInputStream()
1115      */
1116     public final InputStream openStream() throws java.io.IOException {
1117         return openConnection().getInputStream();
1118     }
1119 
1120     /**
1121      * Gets the contents of this URL. This method is a shorthand for:
1122      * <blockquote><pre>
1123      *     openConnection().getContent()
1124      * </pre></blockquote>
1125      *
1126      * @return     the contents of this URL.
1127      * @exception  IOException  if an I/O exception occurs.
1128      * @see        java.net.URLConnection#getContent()
1129      */
1130     public final Object getContent() throws java.io.IOException {
1131         return openConnection().getContent();
1132     }
1133 
1134     /**
1135      * Gets the contents of this URL. This method is a shorthand for:
1136      * <blockquote><pre>
1137      *     openConnection().getContent(classes)
1138      * </pre></blockquote>
1139      *
1140      * @param classes an array of Java types
1141      * @return     the content object of this URL that is the first match of
1142      *               the types specified in the classes array.
1143      *               null if none of the requested types are supported.
1144      * @exception  IOException  if an I/O exception occurs.
1145      * @see        java.net.URLConnection#getContent(Class[])
1146      * @since 1.3
1147      */
1148     public final Object getContent(Class<?>[] classes)
1149     throws java.io.IOException {
1150         return openConnection().getContent(classes);
1151     }
1152 
1153     /**
1154      * The URLStreamHandler factory.
1155      */
1156     private static volatile URLStreamHandlerFactory factory;
1157 
1158     /**
1159      * Sets an application's {@code URLStreamHandlerFactory}.
1160      * This method can be called at most once in a given Java Virtual
1161      * Machine.
1162      *
1163      *<p> The {@code URLStreamHandlerFactory} instance is used to
1164      *construct a stream protocol handler from a protocol name.
1165      *
1166      * <p> If there is a security manager, this method first calls
1167      * the security manager's {@code checkSetFactory} method
1168      * to ensure the operation is allowed.
1169      * This could result in a SecurityException.
1170      *
1171      * @param      fac   the desired factory.
1172      * @exception  Error  if the application has already set a factory.
1173      * @exception  SecurityException  if a security manager exists and its
1174      *             {@code checkSetFactory} method doesn't allow
1175      *             the operation.
1176      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1177      *             int, java.lang.String)
1178      * @see        java.net.URLStreamHandlerFactory
1179      * @see        SecurityManager#checkSetFactory
1180      */
1181     public static void setURLStreamHandlerFactory(URLStreamHandlerFactory fac) {
1182         synchronized (streamHandlerLock) {
1183             if (factory != null) {
1184                 throw new Error("factory already defined");
1185             }
1186             SecurityManager security = System.getSecurityManager();
1187             if (security != null) {
1188                 security.checkSetFactory();
1189             }
1190             handlers.clear();
1191 
1192             // safe publication of URLStreamHandlerFactory with volatile write
1193             factory = fac;
1194         }
1195     }
1196 
1197     private static final URLStreamHandlerFactory defaultFactory = new DefaultFactory();
1198 
1199     private static class DefaultFactory implements URLStreamHandlerFactory {
1200         private static String PREFIX = "sun.net.www.protocol";
1201 
1202         public URLStreamHandler createURLStreamHandler(String protocol) {
1203             String name = PREFIX + "." + protocol + ".Handler";
1204             try {
1205                 @SuppressWarnings("deprecation")
1206                 Object o = Class.forName(name).newInstance();
1207                 return (URLStreamHandler)o;
1208             } catch (ClassNotFoundException x) {
1209                 // ignore
1210             } catch (Exception e) {
1211                 // For compatibility, all Exceptions are ignored.
1212                 // any number of exceptions can get thrown here
1213             }
1214             return null;
1215         }
1216     }
1217 
1218     private static URLStreamHandler lookupViaProperty(String protocol) {
1219         String packagePrefixList =
1220                 GetPropertyAction.privilegedGetProperty(protocolPathProp);
1221         if (packagePrefixList == null) {
1222             // not set
1223             return null;
1224         }
1225 
1226         String[] packagePrefixes = packagePrefixList.split("\\|");
1227         URLStreamHandler handler = null;
1228         for (int i=0; handler == null && i<packagePrefixes.length; i++) {
1229             String packagePrefix = packagePrefixes[i].trim();
1230             try {
1231                 String clsName = packagePrefix + "." + protocol + ".Handler";
1232                 Class<?> cls = null;
1233                 try {
1234                     cls = Class.forName(clsName);
1235                 } catch (ClassNotFoundException e) {
1236                     ClassLoader cl = ClassLoader.getSystemClassLoader();
1237                     if (cl != null) {
1238                         cls = cl.loadClass(clsName);
1239                     }
1240                 }
1241                 if (cls != null) {
1242                     @SuppressWarnings("deprecation")
1243                     Object tmp = cls.newInstance();
1244                     handler = (URLStreamHandler)tmp;
1245                 }
1246             } catch (Exception e) {
1247                 // any number of exceptions can get thrown here
1248             }
1249         }
1250         return handler;
1251     }
1252 
1253     private static Iterator<URLStreamHandlerProvider> providers() {
1254         return new Iterator<>() {
1255 
1256             ClassLoader cl = ClassLoader.getSystemClassLoader();
1257             ServiceLoader<URLStreamHandlerProvider> sl =
1258                     ServiceLoader.load(URLStreamHandlerProvider.class, cl);
1259             Iterator<URLStreamHandlerProvider> i = sl.iterator();
1260 
1261             URLStreamHandlerProvider next = null;
1262 
1263             private boolean getNext() {
1264                 while (next == null) {
1265                     try {
1266                         if (!i.hasNext())
1267                             return false;
1268                         next = i.next();
1269                     } catch (ServiceConfigurationError sce) {
1270                         if (sce.getCause() instanceof SecurityException) {
1271                             // Ignore security exceptions
1272                             continue;
1273                         }
1274                         throw sce;
1275                     }
1276                 }
1277                 return true;
1278             }
1279 
1280             public boolean hasNext() {
1281                 return getNext();
1282             }
1283 
1284             public URLStreamHandlerProvider next() {
1285                 if (!getNext())
1286                     throw new NoSuchElementException();
1287                 URLStreamHandlerProvider n = next;
1288                 next = null;
1289                 return n;
1290             }
1291         };
1292     }
1293 
1294     // Thread-local gate to prevent recursive provider lookups
1295     private static ThreadLocal<Object> gate = new ThreadLocal<>();
1296 
1297     private static URLStreamHandler lookupViaProviders(final String protocol) {
1298         if (gate.get() != null)
1299             throw new Error("Circular loading of URL stream handler providers detected");
1300 
1301         gate.set(gate);
1302         try {
1303             return AccessController.doPrivileged(
1304                 new PrivilegedAction<>() {
1305                     public URLStreamHandler run() {
1306                         Iterator<URLStreamHandlerProvider> itr = providers();
1307                         while (itr.hasNext()) {
1308                             URLStreamHandlerProvider f = itr.next();
1309                             URLStreamHandler h = f.createURLStreamHandler(protocol);
1310                             if (h != null)
1311                                 return h;
1312                         }
1313                         return null;
1314                     }
1315                 });
1316         } finally {
1317             gate.set(null);
1318         }
1319     }
1320 
1321     /**
1322      * Returns the protocol in lower case. Special cases known protocols
1323      * to avoid loading locale classes during startup.
1324      */
1325     static String toLowerCase(String protocol) {
1326         if (protocol.equals("jrt") || protocol.equals("file") || protocol.equals("jar")) {
1327             return protocol;
1328         } else {
1329             return protocol.toLowerCase(Locale.ROOT);
1330         }
1331     }
1332 
1333     /**
1334      * Non-overrideable protocols: "jrt" and "file"
1335      *
1336      * Character-based comparison for performance reasons; also ensures
1337      * case-insensitive comparison in a locale-independent fashion.
1338      */
1339     static boolean isOverrideable(String protocol) {
1340         if (protocol.length() == 3) {
1341             if ((Character.toLowerCase(protocol.charAt(0)) == 'j') &&
1342                     (Character.toLowerCase(protocol.charAt(1)) == 'r') &&
1343                     (Character.toLowerCase(protocol.charAt(2)) == 't')) {
1344                 return false;
1345             }
1346         } else if (protocol.length() == 4) {
1347             if ((Character.toLowerCase(protocol.charAt(0)) == 'f') &&
1348                     (Character.toLowerCase(protocol.charAt(1)) == 'i') &&
1349                     (Character.toLowerCase(protocol.charAt(2)) == 'l') &&
1350                     (Character.toLowerCase(protocol.charAt(3)) == 'e')) {
1351                 return false;
1352             }
1353         }
1354         return true;
1355     }
1356 
1357     /**
1358      * A table of protocol handlers.
1359      */
1360     static Hashtable<String,URLStreamHandler> handlers = new Hashtable<>();
1361     private static final Object streamHandlerLock = new Object();
1362 
1363     /**
1364      * Returns the Stream Handler.
1365      * @param protocol the protocol to use
1366      */
1367     static URLStreamHandler getURLStreamHandler(String protocol) {
1368 
1369         URLStreamHandler handler = handlers.get(protocol);
1370 
1371         if (handler != null) {
1372             return handler;
1373         }
1374 
1375         URLStreamHandlerFactory fac;
1376         boolean checkedWithFactory = false;
1377 
1378         if (isOverrideable(protocol) && jdk.internal.misc.VM.isBooted()) {
1379             // Use the factory (if any). Volatile read makes
1380             // URLStreamHandlerFactory appear fully initialized to current thread.
1381             fac = factory;
1382             if (fac != null) {
1383                 handler = fac.createURLStreamHandler(protocol);
1384                 checkedWithFactory = true;
1385             }
1386 
1387             if (handler == null && !protocol.equalsIgnoreCase("jar")) {
1388                 handler = lookupViaProviders(protocol);
1389             }
1390 
1391             if (handler == null) {
1392                 handler = lookupViaProperty(protocol);
1393             }
1394         }
1395 
1396         synchronized (streamHandlerLock) {
1397             if (handler == null) {
1398                 // Try the built-in protocol handler
1399                 handler = defaultFactory.createURLStreamHandler(protocol);
1400             } else {
1401                 URLStreamHandler handler2 = null;
1402 
1403                 // Check again with hashtable just in case another
1404                 // thread created a handler since we last checked
1405                 handler2 = handlers.get(protocol);
1406 
1407                 if (handler2 != null) {
1408                     return handler2;
1409                 }
1410 
1411                 // Check with factory if another thread set a
1412                 // factory since our last check
1413                 if (!checkedWithFactory && (fac = factory) != null) {
1414                     handler2 = fac.createURLStreamHandler(protocol);
1415                 }
1416 
1417                 if (handler2 != null) {
1418                     // The handler from the factory must be given more
1419                     // importance. Discard the default handler that
1420                     // this thread created.
1421                     handler = handler2;
1422                 }
1423             }
1424 
1425             // Insert this handler into the hashtable
1426             if (handler != null) {
1427                 handlers.put(protocol, handler);
1428             }
1429         }
1430 
1431         return handler;
1432     }
1433 
1434     /**
1435      * @serialField    protocol String
1436      *
1437      * @serialField    host String
1438      *
1439      * @serialField    port int
1440      *
1441      * @serialField    authority String
1442      *
1443      * @serialField    file String
1444      *
1445      * @serialField    ref String
1446      *
1447      * @serialField    hashCode int
1448      *
1449      */
1450     private static final ObjectStreamField[] serialPersistentFields = {
1451         new ObjectStreamField("protocol", String.class),
1452         new ObjectStreamField("host", String.class),
1453         new ObjectStreamField("port", int.class),
1454         new ObjectStreamField("authority", String.class),
1455         new ObjectStreamField("file", String.class),
1456         new ObjectStreamField("ref", String.class),
1457         new ObjectStreamField("hashCode", int.class), };
1458 
1459     /**
1460      * WriteObject is called to save the state of the URL to an
1461      * ObjectOutputStream. The handler is not saved since it is
1462      * specific to this system.
1463      *
1464      * @serialData the default write object value. When read back in,
1465      * the reader must ensure that calling getURLStreamHandler with
1466      * the protocol variable returns a valid URLStreamHandler and
1467      * throw an IOException if it does not.
1468      */
1469     private synchronized void writeObject(java.io.ObjectOutputStream s)
1470         throws IOException
1471     {
1472         s.defaultWriteObject(); // write the fields
1473     }
1474 
1475     /**
1476      * readObject is called to restore the state of the URL from the
1477      * stream.  It reads the components of the URL and finds the local
1478      * stream handler.
1479      */
1480     private synchronized void readObject(java.io.ObjectInputStream s)
1481             throws IOException, ClassNotFoundException {
1482         GetField gf = s.readFields();
1483         String protocol = (String)gf.get("protocol", null);
1484         if (getURLStreamHandler(protocol) == null) {
1485             throw new IOException("unknown protocol: " + protocol);
1486         }
1487         String host = (String)gf.get("host", null);
1488         int port = gf.get("port", -1);
1489         String authority = (String)gf.get("authority", null);
1490         String file = (String)gf.get("file", null);
1491         String ref = (String)gf.get("ref", null);
1492         int hashCode = gf.get("hashCode", -1);
1493         if (authority == null
1494                 && ((host != null && host.length() > 0) || port != -1)) {
1495             if (host == null)
1496                 host = "";
1497             authority = (port == -1) ? host : host + ":" + port;
1498         }
1499         tempState = new UrlDeserializedState(protocol, host, port, authority,
1500                file, ref, hashCode);
1501     }
1502 
1503     /**
1504      * Replaces the de-serialized object with an URL object.
1505      *
1506      * @return a newly created object from deserialized data
1507      *
1508      * @throws ObjectStreamException if a new object replacing this
1509      * object could not be created
1510      */
1511 
1512    private Object readResolve() throws ObjectStreamException {
1513 
1514         URLStreamHandler handler = null;
1515         // already been checked in readObject
1516         handler = getURLStreamHandler(tempState.getProtocol());
1517 
1518         URL replacementURL = null;
1519         if (isBuiltinStreamHandler(handler.getClass().getName())) {
1520             replacementURL = fabricateNewURL();
1521         } else {
1522             replacementURL = setDeserializedFields(handler);
1523         }
1524         return replacementURL;
1525     }
1526 
1527     private URL setDeserializedFields(URLStreamHandler handler) {
1528         URL replacementURL;
1529         String userInfo = null;
1530         String protocol = tempState.getProtocol();
1531         String host = tempState.getHost();
1532         int port = tempState.getPort();
1533         String authority = tempState.getAuthority();
1534         String file = tempState.getFile();
1535         String ref = tempState.getRef();
1536         int hashCode = tempState.getHashCode();
1537 
1538 
1539         // Construct authority part
1540         if (authority == null
1541             && ((host != null && host.length() > 0) || port != -1)) {
1542             if (host == null)
1543                 host = "";
1544             authority = (port == -1) ? host : host + ":" + port;
1545 
1546             // Handle hosts with userInfo in them
1547             int at = host.lastIndexOf('@');
1548             if (at != -1) {
1549                 userInfo = host.substring(0, at);
1550                 host = host.substring(at+1);
1551             }
1552         } else if (authority != null) {
1553             // Construct user info part
1554             int ind = authority.indexOf('@');
1555             if (ind != -1)
1556                 userInfo = authority.substring(0, ind);
1557         }
1558 
1559         // Construct path and query part
1560         String path = null;
1561         String query = null;
1562         if (file != null) {
1563             // Fix: only do this if hierarchical?
1564             int q = file.lastIndexOf('?');
1565             if (q != -1) {
1566                 query = file.substring(q+1);
1567                 path = file.substring(0, q);
1568             } else
1569                 path = file;
1570         }
1571 
1572         // Set the object fields.
1573         this.protocol = protocol;
1574         this.host = host;
1575         this.port = port;
1576         this.file = file;
1577         this.authority = authority;
1578         this.ref = ref;
1579         this.hashCode = hashCode;
1580         this.handler = handler;
1581         this.query = query;
1582         this.path = path;
1583         this.userInfo = userInfo;
1584         replacementURL = this;
1585         return replacementURL;
1586     }
1587 
1588     private URL fabricateNewURL()
1589                 throws InvalidObjectException {
1590         // create URL string from deserialized object
1591         URL replacementURL = null;
1592         String urlString = tempState.reconstituteUrlString();
1593 
1594         try {
1595             replacementURL = new URL(urlString);
1596         } catch (MalformedURLException mEx) {
1597             resetState();
1598             InvalidObjectException invoEx = new InvalidObjectException(
1599                     "Malformed URL:  " + urlString);
1600             invoEx.initCause(mEx);
1601             throw invoEx;
1602         }
1603         replacementURL.setSerializedHashCode(tempState.getHashCode());
1604         resetState();
1605         return replacementURL;
1606     }
1607 
1608     private boolean isBuiltinStreamHandler(String handlerClassName) {
1609         return (handlerClassName.startsWith(BUILTIN_HANDLERS_PREFIX));
1610     }
1611 
1612     private void resetState() {
1613         this.protocol = null;
1614         this.host = null;
1615         this.port = -1;
1616         this.file = null;
1617         this.authority = null;
1618         this.ref = null;
1619         this.hashCode = -1;
1620         this.handler = null;
1621         this.query = null;
1622         this.path = null;
1623         this.userInfo = null;
1624         this.tempState = null;
1625     }
1626 
1627     private void setSerializedHashCode(int hc) {
1628         this.hashCode = hc;
1629     }
1630 
1631     static {
1632         SharedSecrets.setJavaNetURLAccess(
1633                 new JavaNetURLAccess() {
1634                     @Override
1635                     public URLStreamHandler getHandler(URL u) {
1636                         return u.handler;
1637                     }
1638                 }
1639         );
1640     }
1641 }
1642 
1643 final class UrlDeserializedState {
1644     private final String protocol;
1645     private final String host;
1646     private final int port;
1647     private final String authority;
1648     private final String file;
1649     private final String ref;
1650     private final int hashCode;
1651 
1652     public UrlDeserializedState(String protocol,
1653                                 String host, int port,
1654                                 String authority, String file,
1655                                 String ref, int hashCode) {
1656         this.protocol = protocol;
1657         this.host = host;
1658         this.port = port;
1659         this.authority = authority;
1660         this.file = file;
1661         this.ref = ref;
1662         this.hashCode = hashCode;
1663     }
1664 
1665     String getProtocol() {
1666         return protocol;
1667     }
1668 
1669     String getHost() {
1670         return host;
1671     }
1672 
1673     String getAuthority () {
1674         return authority;
1675     }
1676 
1677     int getPort() {
1678         return port;
1679     }
1680 
1681     String getFile () {
1682         return file;
1683     }
1684 
1685     String getRef () {
1686         return ref;
1687     }
1688 
1689     int getHashCode () {
1690         return hashCode;
1691     }
1692 
1693     String reconstituteUrlString() {
1694 
1695         // pre-compute length of StringBuffer
1696         int len = protocol.length() + 1;
1697         if (authority != null && authority.length() > 0)
1698             len += 2 + authority.length();
1699         if (file != null) {
1700             len += file.length();
1701         }
1702         if (ref != null)
1703             len += 1 + ref.length();
1704         StringBuilder result = new StringBuilder(len);
1705         result.append(protocol);
1706         result.append(":");
1707         if (authority != null && authority.length() > 0) {
1708             result.append("//");
1709             result.append(authority);
1710         }
1711         if (file != null) {
1712             result.append(file);
1713         }
1714         if (ref != null) {
1715             result.append("#");
1716             result.append(ref);
1717         }
1718         return result.toString();
1719     }
1720 }