private static String getQualifiedName(String filePath, int rootPathLength) {
    boolean isClassFile = SystemInfo.isFileSystemCaseSensitive
                          ? StringUtil.endsWith(filePath, CLASS_EXTENSION)
                          : StringUtil.endsWithIgnoreCase(filePath, CLASS_EXTENSION);
    if (!isClassFile) return null;
    String withoutExtension = filePath.substring(rootPathLength, filePath.length() - CLASS_EXTENSION.length());
    return withoutExtension.replace('/', '.');
  }
private static String getQualifiedName(String filePath, int rootPathLength)