*     was indeed modified, unless {@code oldCount == newCount}.
   * @throws IllegalArgumentException if {@code oldCount} or {@code newCount} is negative
   * @throws NullPointerException if {@code element} is null and the implementation does not permit
   *     null elements. Note that if {@code oldCount} and {@code newCount} are both zero, the
   *     implementor may optionally return {@code true} instead.
   */
  @CanIgnoreReturnValue

     * <code>path.separator</code> system property. For example, on Mac OS X: <code>":"</code>
     */
    public static final String PATH_SEPARATOR = System.getProperty("path.separator");

    /**
     * <code>os.name</code> system property. Example: <code>Mac OS X</code>
     */
    public static final String OS_NAME = System.getProperty("os.name");

    /**
     * <code>java.io.tmpdir</code> system property. Example: /tmp
     */

 * and the field type can be {@link org.apache.maven.api.Node Node},
 * {@code List<}{@link org.apache.maven.api.Node Node}{@code >},
 * {@link org.apache.maven.api.services.DependencyResolverResult DependencyResolverResult},
 * {@code List<}{@link java.nio.file.Path Path}{@code >},

   * Multimap} entries in two distinct modes:
   *
   * <ul>
   *   <li>To output a separate entry for each key-value pair, pass {@code multimap.entries()} to a
   *       {@code MapJoiner} method that accepts entries as input, and receive output of the form
   *       {@code key1=A&key1=B&key2=C}.
   *   <li>To output a single entry for each key, pass {@code multimap.asMap()} to a {@code

 * example round-trip using {@link com.google.common.primitives.Doubles#stringConverter}:
 *
 * <ol>
 *   <li>{@code stringConverter().convert("1.00")} returns the {@code Double} value {@code 1.0}
 *   <li>{@code stringConverter().reverse().convert(1.0)} returns the string {@code "1.0"} --
 *       <i>not</i> the same string ({@code "1.00"}) we started with
 * </ol>
 *

  }

  /** See https://api.slack.com/methods/oauth.access. */
  public OAuthSession exchangeCode(String code, HttpUrl redirectUrl) throws IOException {
    HttpUrl url = baseUrl.newBuilder("oauth.access")
        .addQueryParameter("client_id", clientId)
        .addQueryParameter("client_secret", clientSecret)
        .addQueryParameter("code", code)
        .addQueryParameter("redirect_uri", redirectUrl.toString())
        .build();

    }

    /**
     * Get singleton context
     *
     * The singleton context will use system properties for configuration as well as values specified in a file
     * specified through this <code>jcifs.properties</code> system property.
     *
     * @return a global context, initialized on first call
     */
    public static synchronized final SingletonContext getInstance() {
        if (INSTANCE == null) {
            try {

     *
     * @param artifact           artifact we are interested in. Only <code>groupid</code> and <code>artifactId</code>
     *                           are needed, for instance the following code will work
     *                           <code>artifactFactory.createProjectArtifact( "org.apache.maven", "maven", "" )</code>
     * @param localRepository    local repository

 * <p>
 * This extensible enum has two defined values, {@link #MAIN} and {@link #TEST},
 * but can be extended by registering a {@code org.apache.maven.api.spi.ProjectScopeProvider}.
 * <p>
 * Implementation must have {@code equals()} and {@code hashCode()} implemented, so implementations of this interface
 * can be used as keys.
 *
 * @since 4.0.0
 */
@Experimental
@Immutable

 * <i>other type</i> of supplier is expected, use the method reference {@code supplier::get}. A
 * future version of {@code com.google.common.base.Supplier} will be made to <i>extend</i> {@code
 * java.util.function.Supplier}, making conversion code necessary only in one direction. At that
 * time, this interface will be officially discouraged.
 *
 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible