Apache Commons CLI - Boolean Option

Overview

A boolean option is represented on a command line by its presence. For example, if option is present, then its value is true, otherwise, it is considered as false. Consider the case, where we are printing current date and if -t flag is present. Then, we will print time too.

Define an Optional Argument

Options options = new Options();
// pass required as false to make option as non-mandatory
options.addOption("t", false, "display time");

Check if Argument is passed then act accordingly

if(cmd.hasOption("t")) {
   System.out.print(" " + hour + ":" + min + ":" + sec);
}

Example - Handling Boolean Option in Command Line Arguments

CLITester.java

package com.tutorialspoint;

import java.util.Calendar;
import java.util.Date;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.DefaultParser;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;

public class CLITester {
   public static void main(String[] args) throws ParseException {
      Options options = new Options();
      options.addOption("t", false, "display time");
      
      CommandLineParser parser = new DefaultParser();
      CommandLine cmd = parser.parse( options, args);

      Calendar date = Calendar.getInstance();
      int day = date.get(Calendar.DAY_OF_MONTH);
      int month = date.get(Calendar.MONTH);
      int year = date.get(Calendar.YEAR);

      int hour = date.get(Calendar.HOUR);
      int min = date.get(Calendar.MINUTE);
      int sec = date.get(Calendar.SECOND);

      System.out.print(day + "/" + month + "/" + year);
      if(cmd.hasOption("t")) {
         System.out.print(" " + hour + ":" + min + ":" + sec);
      }
   }
}

Output

Run the file without passing any option and see the result −

java CLITester
27/7/2025

Run the file, while passing -t as option and see the result −

java CLITester -t
27/7/2025 4:40:11