Generate Java code from a regex

import java.util.regex.*;
import java.util.*;

public class RegexDemo {
    public static void main(String[] args) {
        String input = "Reach alice@example.com or bob@test.org.";
        Pattern p = Pattern.compile("\\\\b\\\\w+@\\\\w+\\\\.\\\\w+\\\\b", 0);

        Matcher m = p.matcher(input);
        boolean isMatch = m.find();
        String first = isMatch ? m.group(0) : null;

        List<String> all = new ArrayList<>();
        Matcher mAll = p.matcher(input);
        while (mAll.find()) all.add(mAll.group(0));

        String replaced = p.matcher(input).replaceAll("[email]");
        String[] parts = p.split(input);

        System.out.println("isMatch=" + (first != null));
        System.out.println("first=" + first);
        System.out.println("all=" + all);
        System.out.println("replaced=" + replaced);
        System.out.println("parts=" + Arrays.toString(parts));
    }
}