code: public String getAbsoluteRfsPathRelativeToWebApplication(String path) {
  
          if ((path == null) || (getWebApplicationRfsPath() == null)) {
              return null;
          }
          // check for absolute path is system depended, let's just use the standard check
          File f = new File(path);
          if (f.isAbsolute()) {
              // apparently this is an absolute path already
              path = f.getAbsolutePath();
              if (f.isDirectory() && !path.endsWith(File.separator)) {
                  // make sure all folder paths end with a separator
                  path = path.concat(File.separator);
              }
              return path;
          }
          return CmsFileUtil.normalizePath(getWebApplicationRfsPath() + path);
      }
docs: Returns an absolute path (to a directory or a file in the "real" file system) from a path relative to
  the web application folder of OpenCms.<p>
  
  If the provided path is already absolute, then it is returned unchanged.
  If the provided path is a folder, the result will always end with a folder separator.<p>
  
  @param path the path (relative) to generate an absolute path from
  @return an absolute path (to a directory or a file) from a path relative to the web application folder of OpenCms