Android Java helper class for handling HTTP GET requests. (Requires Java 11+)

HttpClientManager.java

package com.shilocity.http;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.function.Consumer;

public class HttpClientManager {
    public static Future<?> sendAsync(String url) {
        return sendAsync(url, null);
    }

    public static Future<?> sendAsync(String url, Consumer<HttpClientManagerResult> onFinished) {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        return executor.submit(
                () -> {
                    HttpClientManagerResult result = send(url);
                    if (onFinished != null)
                        onFinished.accept(result);

                    executor.shutdown();
                });
    }

    public static HttpClientManagerResult send(String url) {
        HttpURLConnection urlConnection = null;
        try {
            urlConnection = (HttpURLConnection) new URL(url).openConnection();
            InputStream inputStream = new BufferedInputStream(urlConnection.getInputStream());
            String response = readInputStream(inputStream);

            urlConnection.disconnect();
            return new HttpClientManagerResult(response);
        } catch (Exception exception) {
            if (urlConnection != null)
                urlConnection.disconnect();
            return new HttpClientManagerResult(exception);
        }
    }

    public static String addressToUrl(String ip) {
        return addressToUrl(ip, 80);
    }

    public static String addressToUrl(String ip, int port) {
        return addressToUrl(ip, port, true);
    }

    public static String addressToUrl(String ip, int port, boolean isSecure) {
        String scheme = isSecure ? "https" : "http";
        String url = scheme + "://" + ip;
        if (port != 80)
            url += ":" + port;
        return url;
    }

    private static String readInputStream(InputStream inputStream) throws Exception {
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        boolean isNewLine = false;

        for (String line = bufferedReader.readLine(); line != null; line = bufferedReader.readLine()) {
            if (isNewLine)
                stringBuilder.append("\n");
            stringBuilder.append(line);
            isNewLine = true;
        }

        inputStream.close();
        return stringBuilder.toString();
    }
}

HttpClientManagerResult.java

package com.shilocity.http;

public class HttpClientManagerResult {
    public String response;
    public Exception exception;

    public HttpClientManagerResult(String response) {
        this.response = response;
        this.exception = null;
    }

    public HttpClientManagerResult(Exception exception) {
        this.response = null;
        this.exception = exception;
    }
}

MainActivity.java

package de.xida.myapplication;

import android.os.Bundle;
import android.util.Log;

import androidx.appcompat.app.AppCompatActivity;

import com.shilocity.http.HttpClientManager;
import com.shilocity.http.HttpClientManagerResult;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        String ip = "www.google.com";
        int port = 80;
        boolean isSecure = true;

        String url = HttpClientManager.addressToUrl(ip, port, isSecure);

        exampleSendAsync(url, isSecure);
    }

    static void exampleSendAsync(String url, boolean isSecure) {
        HttpClientManager.sendAsync(url,
                (result) -> onExampleSendFinished(result));
    }

    static void onExampleSendFinished(HttpClientManagerResult result) {
        if (result.exception != null) {
            Log.w("===", result.exception);
            // todo: handle error here
            return;
        }

        Log.d("===", result.response);
        // todo: handle http body here
    }
}