Example
private final OkHttpClient client = new OkHttpClient();
  public void run() throws Exception {
    Request request = new Request.Builder()
        .url(yourUrl)
        .build();
    client.newCall(request).enqueue(new Callback() {
      @Override public void onFailure(Call call, IOException e) {
        e.printStackTrace();
      }
      @Override
      public void onResponse(Call call, Response response) throws IOException {
        if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
        Headers responseHeaders = response.headers();
        System.out.println(response.body().string());
      }
    });
  }