code: public synchronized com.sun.tools.javac.util.List<String> getFiles(RelativeDirectory path) {
          try {
              checkIndex();
  
              DirectoryEntry de = directories.get(path);
              com.sun.tools.javac.util.List<String> ret = de == null ? null : de.getFiles();
  
              if (ret == null) {
                  return com.sun.tools.javac.util.List.<String>nil();
              }
              return ret;
          }
          catch (IOException e) {
              return com.sun.tools.javac.util.List.<String>nil();
          }
      }
docs: Returns a javac List of filenames within a directory in the ZipFileIndex.