Q: android OkHttp clear disk cache image entry Just like picasso has Picasso.with(context).invalidate(url) , 
Does okhttp have any mechanism for clearing a disk cache entry given a key?

A: As the user polbins stated here this seems like can be achieved like this.
public static void removeFromCache(String urlString) {
    try {
        Iterator<String> it = mCache.urls();

        while (it.hasNext()) {
            String next = it.next();

            if (next.contains(urlString)) {
                it.remove();
            }   
        }   
    } catch (IOException e) {
        e.printStackTrace();
    }   
}

mCache instance is the cache instance that you set to OkHttpClient, like this.
Cache cache = new Cache(httpCacheDirectory, 10 * 1024 * 1024);
        OkHttpClient client = new OkHttpClient();
        client.setCache(cache);

