How to parse command line arguments in Java. For more details see https://codeandsolder.blogspot.com/2017/09/how-to-parse-command-line-arguments-in-java.html

CommandLine.java

import java.util.HashMap;
import java.util.Map;

public class CommandLine {

    public static Parameters parse(String[] args) {
        Parameters params = new Parameters();

        int i = 0;
        while (i < args.length) {
            switch(args[i]) {
                case "--host":
                    if (i == args.length - 1) {
                        throw new RuntimeException("No path specified for --host option");
                    }

                    params.add("host", args[++i]);
                    break;
                case "--port":
                    if (i == args.length - 1) {
                        throw new RuntimeException("No path specified for --port option");
                    }

                    params.add("port", Integer.parseInt(args[++i]));
                    break;
                case "--verbose":
                    params.add("verbose", Boolean.TRUE);
                    break;
                default:
                    throw new RuntimeException("Unexpected parameter: " + args[i]);
            }

            i++;
        }

        return params;
    }

    public static class Parameters {

        private final Map<String, Object> params = new HashMap<>();

        public void add(String name, Object value) {
            params.put(name, value);
        }

        public String getString(String name, String defaultValue) {
            Object value = params.get(name);
            if (value == null) {
                return defaultValue;
            }

            if (value instanceof String) {
                return (String) value;
            }

            throw new RuntimeException(
                    String.format("'%s' doesn't look like a string: %s", name, value));
        }

        public int getInteger(String name, int defaultValue) {
            Object value = params.get(name);
            if (value == null) {
                return defaultValue;
            }

            if (value instanceof Integer) {
                return (Integer) value;
            }

            throw new RuntimeException(
                    String.format("'%s' doesn't look like an integer: %s", name, value));
        }

        public boolean getBoolean(String name, boolean defaultValue) {
            Object value = params.get(name);
            if (value == null) {
                return defaultValue;
            }

            if (value instanceof Boolean) {
                return (Boolean) value;
            }

            throw new RuntimeException(
                    String.format("'%s' doesn't look like an integer: %s", name, value));
        }
    }

    public static void main(String[] args) {
        Parameters params = parse(args);
        System.out.println("host    = " + params.getString("host", "localhost"));
        System.out.println("port    = " + params.getInteger("port", 80));
        System.out.println("verbose = " + params.getBoolean("verbose", false));
    }
}