You will need to include the JSON Simple library in your project (this can also be used on the SDN): https://github.com/fangyidong/json-simple RSExchange.java import org.json.simple.JSONObject; import org.json.simple.parser.JSONParser; import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.URL; import java.net.URLConnection; import java.util.HashMap; import java.util.Map; import java.util.Optional; public final class RSExchange { private final JSONO