My common Helper class used in a lot of my projects

Helper.java

package com.gmatrixgames.fn.discord.utils;

import kotlin.text.Charsets;
import org.apache.commons.io.IOUtils;
import org.apache.wink.json4j.JSONException;
import org.apache.wink.json4j.JSONObject;

import javax.net.ssl.HttpsURLConnection;
import java.awt.*;
import java.io.*;
import java.math.BigDecimal;
import java.net.URL;
import java.nio.channels.ReadableByteChannel;
import java.nio.charset.StandardCharsets;
import java.text.DecimalFormat;
import java.time.Instant;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Stream;

public class Helper {
    public static String toStringUnixTime(Instant i) {
        BigDecimal nanos = BigDecimal.valueOf(i.getNano(), 9);
        BigDecimal seconds = BigDecimal.valueOf(i.getEpochSecond());
        BigDecimal total = seconds.add(nanos);
        DecimalFormat df = new DecimalFormat("#.#########");
        return df.format(total);
    }

    public static Color hex2Rgb(String colorStr) {
        return new Color(Integer.valueOf(colorStr.substring(1, 3), 16), Integer.valueOf(colorStr.substring(3, 5), 16), Integer.valueOf(colorStr.substring(5, 7), 16));
    }

    public static String center(String text, int len) {
        String out = String.format("%" + len + "s%s%" + len + "s", "", text, "");
        float mid = (out.length() / 2f);
        float start = mid - (len / 2f);
        float end = start + len;
        return out.substring((int) start, (int) end);
    }

    public static String postToHastebin(String text, boolean raw) throws IOException {
        byte[] postData = text.getBytes(StandardCharsets.UTF_8);
        int postDataLength = postData.length;

        String requestURL = "https://hasteb.in/documents";
        URL url = new URL(requestURL);
        HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
        conn.setDoOutput(true);
        conn.setInstanceFollowRedirects(false);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("User-Agent", "Hastebin Java Api");
        conn.setRequestProperty("Content-Length", Integer.toString(postDataLength));
        conn.setUseCaches(false);

        String response = null;
        DataOutputStream wr;
        try {
            wr = new DataOutputStream(conn.getOutputStream());
            wr.write(postData);
            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            response = reader.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }

        if (response.contains("\"key\"")) {
            response = response.substring(response.indexOf(":") + 2, response.length() - 2);

            String postURL = raw ? "https://hasteb.in/raw/" : "https://hasteb.in/";
            response = postURL + response;
        }

        return response;
    }

    public static String streamAsString(InputStream st) {
        Scanner sc = new Scanner(st);
        StringBuilder sb = new StringBuilder();
        while (sc.hasNext()) {
            sb.append(sc.nextLine());
        }

        return sb.toString();
    }

    public static String alphabeticalOrder(List<?> list, Boolean newline) {
        Object[] array = new Object[list.size()];
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < list.size(); i++) {
            array[i] = list.get(i);
        }
        array = Stream.of(array).sorted().toArray(Object[]::new);
        for (Object s : array) {
            if (newline) {
                sb.append(s).append("\n");
            } else {
                sb.append(s);
            }
        }

        return sb.toString();
    }
}