Объясните где ошибся
package com.javarush.task.task15.task1527;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.*;
import static java.lang.Double.parseDouble;
/*
Парсер реквестов
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String url = reader.readLine();
Map<String, List<String>> filtered = getQueryParams(url);
List<String> list = new ArrayList<>(filtered.keySet());
for(int x = 0; x < list.size(); x++) {
System.out.print(list.get(x) + " ");
}
System.out.println("");
if(filtered.containsKey("obj")) {
String s = Arrays.toString(new List[]{filtered.get("obj")})
.replace("[", "")
.replace("]", "");
try {
alert(Double.parseDouble(s));
} catch (NumberFormatException ex) {
alert(s);
}
}
}
public static void alert(double value) {
System.out.println("double: " + value);
}
public static void alert(String value) {
System.out.println("String: " + value);
}
public static Map<String, List<String>> getQueryParams(String url) {
try {
Map<String, List<String>> params = new HashMap<String, List<String>>();
String[] urlParts = url.split("\\?");
if (urlParts.length > 1) {
String query = urlParts[1];
for (String param : query.split("&")) {
String[] pair = param.split("=");
String key = URLDecoder.decode(pair[0], "UTF-8");
String value = "";
if (pair.length > 1) {
value = URLDecoder.decode(pair[1], "UTF-8");
}
List<String> values = params.get(key);
if (values == null) {
values = new ArrayList<String>();
params.put(key, values);
}
values.add(value);
}
}
return params;
} catch (UnsupportedEncodingException ex) {
throw new AssertionError(ex);
}
}
}