return subtype;
  }

  /**
   * Returns true if this type is a supertype of the given {@code type}. "Supertype" is defined
   * according to <a
   * href="http://docs.oracle.com/javase/specs/jls/se8/html/jls-4.html#jls-4.5.1">the rules for type
   * arguments</a> introduced with Java generics.
   *
   * @since 19.0
   */
  public final boolean isSupertypeOf(TypeToken<?> type) {

    return subtype;
  }

  /**
   * Returns true if this type is a supertype of the given {@code type}. "Supertype" is defined
   * according to <a
   * href="http://docs.oracle.com/javase/specs/jls/se8/html/jls-4.html#jls-4.5.1">the rules for type
   * arguments</a> introduced with Java generics.
   *
   * @since 19.0
   */
  public final boolean isSupertypeOf(TypeToken<?> type) {

                if (password != null) {
                    // Cipher uses Strings
                    passwd = String.copyValueOf(password);

                    // Sun/Oracle advises to empty the char array
                    java.util.Arrays.fill(password, ' ');
                }
            }

            DefaultPlexusCipher cipher = new DefaultPlexusCipher();

 * points</a> in the range {@code 0x10000} to {@code 0x10FFFF} which includes the majority of
 * assigned characters, including important CJK characters and emoji.
 *
 * <p>Supplementary characters are <a
 * href="https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html#supplementary">encoded
 * into a {@code String} using surrogate pairs</a>, and a {@code CharMatcher} treats these just as

 * points</a> in the range {@code 0x10000} to {@code 0x10FFFF} which includes the majority of
 * assigned characters, including important CJK characters and emoji.
 *
 * <p>Supplementary characters are <a
 * href="https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html#supplementary">encoded
 * into a {@code String} using surrogate pairs</a>, and a {@code CharMatcher} treats these just as

   * try-catch block.
   *
   * If you think you would use this method, let us know. You might also look into the
   * Fork-Join framework: http://docs.oracle.com/javase/tutorial/essential/concurrency/forkjoin.html
   */

                            }
                        }
                    }
                }
                catch ( SmbException se ) {
                    /*
                     * Oracle FilesOnline version 9.0.4 doesn't send '.' and '..' so
                     * listFiles may generate undesirable "cannot find
                     * the file specified".
                     */

   * try-catch block.
   *
   * If you think you would use this method, let us know. You might also look into the
   * Fork-Join framework: http://docs.oracle.com/javase/tutorial/essential/concurrency/forkjoin.html
   */

See link:{gradle-issues}20969[gradle/gradle#20969].

[[config_cache:not_yet_implemented:java_serialization]]
=== Java Object Serialization

Gradle allows objects that support the link:https://docs.oracle.com/javase/8/docs/platform/serialization/spec/serialTOC.html[Java Object Serialization] protocol to be stored in the configuration cache.

The implementation is currently limited to serializable classes that

[source,properties]
----
systemProp.javax.xml.accessExternalDTD=http
----

Note that this will enable HTTP access to external DTDs for the whole build JVM.
See the link:https://docs.oracle.com/en/java/javase/13/security/java-api-xml-processing-jaxp-security-guide.html#GUID-8CD65EF5-D113-4D5C-A564-B875C8625FAC[JAXP documentation] for more details.

=== Deprecations

[[generate_maven_pom_method_deprecations]]