HTTPUtil.java

public final class HTTPUtil {

    private static Map<String, String> properties = new HashMap<>();

    public static void withRequestProperty(String key, String value) {
        properties.put(key, value);
    }

    public static void removeProperty(String key) {
        properties.remove(key);
    }

    public static JsonObject makeRequest(String url, String method) {
        JsonObject result = null;

        try {
            HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
            connection.setRequestMethod(method);
            connection.setDoOutput(false);

            properties.forEach(connection::setRequestProperty);

            try(BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8))) {
                StringBuilder response = new StringBuilder();
                String line = null;
                while((line = reader.readLine()) != null) {
                    response.append(line.trim());
                }
                result = (JsonObject) new JsonParser().parse(response.toString());
            }

            connection.disconnect();
        } catch(IOException exception) {
            Logger.log(Logger.Level.SEVERE, "[ctx:e-%s]", exception.getLocalizedMessage());
        }

        properties.clear();
        return result;
    }

    public static JsonObject makeRequest(String url, String method, JsonObject body) {
        JsonObject result = null;

        try {
            HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
            connection.setRequestMethod(method);
            connection.setDoOutput(true);

            properties.forEach(connection::setRequestProperty);

            try(DataOutputStream writer = new DataOutputStream(connection.getOutputStream())) {
                byte[] input = body.toString().getBytes(StandardCharsets.UTF_8);
                writer.write(input, 0, input.length);
            }

            try(BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8))) {
                StringBuilder response = new StringBuilder();
                String line = null;
                while((line = reader.readLine()) != null) {
                    response.append(line.trim());
                }
                result = (JsonObject) new JsonParser().parse(response.toString());
            }

            connection.disconnect();
        } catch(IOException exception) {
            Logger.log(Logger.Level.SEVERE, "[ctx:e-%s]", exception.getLocalizedMessage());
        }

        properties.clear();
        return result;
    }

}