static Method getMainMethod(PrintStream ostream, Class<?> clazz) {

  {- -------------------------------------------
  (1) class 引数で指定されたクラスの main() メソッドを取得する.
      もし存在しなければ, ここで abort.
      ---------------------------------------- -}

            String classname = clazz.getName();
            Method method = null;
            try {
                method = clazz.getMethod("main", String[].class);
            } catch (NoSuchMethodException nsme) {
                abort(ostream, null, "java.launcher.cls.error4", classname);
            }

  {- -------------------------------------------
  (1) 取得した main() メソッドが, static でかつ返値が void であることを確認する.
      もしそうでなければ, ここで abort.
      ---------------------------------------- -}

            /*
             * getMethod (above) will choose the correct method, based
             * on its name and parameter type, however, we still have to
             * ensure that the method is static and returns a void.
             */
            int mod = method.getModifiers();
            if (!Modifier.isStatic(mod)) {
                abort(ostream, null, "java.launcher.cls.error2", "static", classname);
            }
            if (method.getReturnType() != java.lang.Void.TYPE) {
                abort(ostream, null, "java.launcher.cls.error3", classname);
            }

  {- -------------------------------------------
  (1) 結果をリターン
      ---------------------------------------- -}

            return method;
        }