/**
   * Determines whether two possibly-null objects are equal. Returns:
   *
   * <ul>
   *   <li>{@code true} if {@code a} and {@code b} are both null.
   *   <li>{@code true} if {@code a} and {@code b} are both non-null and they are equal according to
   *       {@link Object#equals(Object)}.
   *   <li>{@code false} in all other situations.
   * </ul>
   *

 * actions taken by the java garbage collection system:
 *
 * <ul>
 *   <li>invoking the {@code finalize} methods of unreachable objects
 *   <li>clearing weak references to unreachable referents
 *   <li>enqueuing weak references to unreachable referents in their reference queue
 * </ul>
 *

 *
 * <ul>
 *   <li><b>Shallow immutability.</b> Elements can never be added, removed or replaced in this
 *       collection. This is a stronger guarantee than that of {@link
 *       Collections#unmodifiableCollection}, whose contents change whenever the wrapped collection
 *       is modified.
 *   <li><b>Null-hostility.</b> This collection will never contain a null element.

     * <li>The parent uses aggregation and refers to the child via the modules section</li>
     * <li>The module path to the child is considered to
     * point at the POM rather than its base directory if the path ends with ".xml" (ignoring case)</li>
     * <li>The name of the child's base directory matches the artifact id of the child.</li>
     * </ul>

 * </p>
 * <ul>
 * <li>{@literal file}</li>
 * <li>{@literal jar}</li>
 * <li>{@literal wsjar} (WebShpere独自プロトコル、{@literal jar}の別名)</li>
 * <li>{@literal zip} (WebLogic独自プロトコル、通常のZipファイルは{@literal jar}プロトコルを使用してください)</li>
 * <li>{@literal code-source} (Oracle AS(OC4J)独自プロトコル)</li>
 * <li>{@literal vfsfile} (JBossAS5独自プロトコル、{@literal file}の別名)</li>
 * <li>{@literal vfszip} (JBossAS5独自プロトコル)</li>
 * </ul>
 *
 * @author koichik

     * <p>
     * Supported filters:
     * <ul>
     *     <li>"h" or "h(num)" - highest version or top list of highest ones filter</li>
     *     <li>"l" or "l(num)" - lowest version or bottom list of lowest ones filter</li>
     *     <li>"s" - contextual snapshot filter</li>
     *     <li>"e(G:A:V)" - predicate filter (leaves out G:A:V from range, if hit, V can be range)</li>
     * </ul>

 *
 * <p>For instance, if <i>steps</i> is 5, one example sequence that will be tested is:
 *
 * <ol>
 *   <li>remove();
 *   <li>hasNext()
 *   <li>hasNext();
 *   <li>remove();
 *   <li>next();
 * </ol>
 *
 * <p>This particular order of operations may be unrealistic, and testing all 3^5 of them may be

     * <p><b>Algorithm:</b>
     * If the given path is a directory, then there is a choice:
     * </p>
     * <ul>
     *   <li><b>Package hierarchy:</b> if a {@code module-info.class} file is found at the root,
     *       then builds a singleton map with the module name declared in that descriptor.</li>
     *   <li><b>Module hierarchy:</b> if {@code module-info.class} files are found in sub-directories,

    /**
     * クラスローダを返します。
     * <p>
     * クラスローダは以下の順で検索します。
     * </p>
     * <ol>
     * <li>呼び出されたスレッドにコンテキスト・クラスローダが設定されている場合はそのコンテキスト・クラスローダ</li>
     * <li>ターゲット・クラスをロードしたクラスローダを取得できればそのクラスローダ</li>
     * <li>このクラスをロードしたクラスローダを取得できればそのクラスローダ</li>
     * <li>システムクラスローダを取得できればそのクラスローダ</li>
     * </ol>
     * <p>
     * ただし、ターゲット・クラスをロードしたクラスローダとこのクラスをロードしたクラスローダの両方が取得できた場合で、

 *
 * <p>For instance, if <i>steps</i> is 5, one example sequence that will be tested is:
 *
 * <ol>
 *   <li>remove();
 *   <li>hasNext()
 *   <li>hasNext();
 *   <li>remove();
 *   <li>next();
 * </ol>
 *
 * <p>This particular order of operations may be unrealistic, and testing all 3^5 of them may be