OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url(API_URL).build();
client.newCall(request).enqueue(new Callback() {
    @Override
    public void onResponse(Call call, Response response) throws IOException {
        List<Item> items = parseItemsFromJson(response.body().string());
        recommendAdapter.updateItems(items);
        startAutoSlide();
    }
});

Runnable sliderRunnable = () -> {
    recommendCurrentPage = (recommendCurrentPage + 1) % totalRecommendItems;
    recommendViewPager.setCurrentItem(recommendCurrentPage, true);

    rankCurrentPage = (rankCurrentPage + 1) % totalRankItems;
    rankViewPager.setCurrentItem(rankCurrentPage, true);

    sliderHandler.postDelayed(this, 3000);
};
sliderHandler.postDelayed(sliderRunnable, 3000);

JSONObject root = new JSONObject(jsonData);
JSONArray contents = root.getJSONArray("contents");
for (int i = 0; i < contents.length(); i++) {
    JSONObject obj = contents.getJSONObject(i);
    items.add(new Item(
        obj.getString("Category"),
        obj.getString("Title"),
        obj.getString("증권사"),
        obj.getString("PDF URL"),
        obj.getString("작성일"),
        obj.getString("Views"),
        obj.getString("Content"),
        obj.getString("PDF Content")
    ));
}