public synchronized void close() throws IOException {
    if (journalWriter == null) {
      return; // Already closed.
    }
    for (Entry entry : new ArrayList<Entry>(lruEntries.values())) {
      if (entry.currentEditor != null) {
        entry.currentEditor.abort();
      }
    }
    trimToSize();
    journalWriter.close();
    journalWriter = null;
  }
Closes this cache. Stored values will remain on the filesystem.
core/src/main/java/com/bumptech/glide/disklrucache/DiskLruCache.java