无法获取响应/状态代码，始终使用HttpUrlConnection获取空白异常

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpClientExample {
    public static void main(String[] args) {
        HttpURLConnection connection = null;
        try {
            URL url = new URL("http://example.com");
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setConnectTimeout(5000);
            connection.setReadTimeout(5000);

            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

            InputStream inputStream;
            if (responseCode >= 400) {
                inputStream = connection.getErrorStream();
            } else {
                inputStream = connection.getInputStream();
            }

            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
            String line;
            StringBuilder response = new StringBuilder();
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            reader.close();

            System.out.println("Response Body: " + response.toString());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
        }
    }
}