Clearing Terminal Screen in Java

Question

I tried to make a Simple Clock in Java

My Expected Output was 00:00:00 // Showing Time

My Actual Output Was

00:00:00
00:00:01
00:00:02
.......

I tried many things and was unable to clear previous output after being printed

Thanks for Reading, Hope somebody will give a valuable feedback

Code:

package com.company.Time;

import java.util.Scanner;

import java.util.Date;


public class Main {

    



    public static void main(String[] args) {
        System.out.println("Enter Time");
        System.out.println("Enter Hour :");
        Scanner sc = new Scanner(System.in);
        int h = sc.nextInt();

        System.out.println("Enter Minutes :");
        Scanner sc2 = new Scanner(System.in);
        int m = sc2.nextInt();

        System.out.println("Enter Seconds :");
        Scanner sc3 = new Scanner(System.in);
        int s = sc3.nextInt();



        int i = 0;

        try {
            while (i < 1)
            {
                for (; h < 24; h++)
                {

                    for (; m < 60; m++)
                    {
                        for (; s < 60; s++)
                        {
                            System.out.println(h + ":" + m + ":" + s);
                            System.out.print("\u000C");
                            Thread.sleep(1000);

                        }

                        s = 0;

                    }
                    m = 0;
                }
            }
        }

        catch(Exception exception)
        {
            System.out.println("Ushh");
        }

    }
}

Java's console support is rudimentary, it doesn't, by default, support things like "clearing" or cursor re-positioning. You might be able to fake it by using a backspace character for [example](https://stackoverflow.com/questions/15843202/how-to-show-percentage-progress-of-a-downloading-file-in-java-consolewithout-ui/15846788#15846788) — MadProgrammer, Jan 14 '22 at 07:40

score 1 · Accepted Answer · answered Jan 14 '22 at 07:44

Replace this:

System.out.println(h + ":" + m + ":" + s);
System.out.print("\u000C");

With this:

System.out.print(h + ":" + m + ":" + s + "\r");

The carriage return symbol (\r) returns the cursor at the start of the line. You must use print() and not println() for it to work. If the program jumps to a new line, the previous line is left as is.

score 0 · Answer 2 · answered Jan 14 '22 at 07:52

public static void main(String[] args) {
        System.out.println("Enter Time");
        System.out.println("Enter Hour :");
        Scanner sc = new Scanner(System.in);
        int h = sc.nextInt();

        System.out.println("Enter Minutes :");
        Scanner sc2 = new Scanner(System.in);
        int m = sc2.nextInt();

        System.out.println("Enter Seconds :");
        Scanner sc3 = new Scanner(System.in);
        int s = sc3.nextInt();



        int i = 0;

        try {
            while (i < 1)
            {
                for (; h < 24; h++)
                {

                    System.out.print(h+":");
                    for (; m < 60; m++)
                    {
                        System.out.print(m+":");
                        for (; s < 60; s++)
                        {
                            System.out.print(h + ":" + m + ":" + s);
                            Thread.sleep(1000);
                            System.out.print("\r");
                        }

                        s = 0;

                    }
                    m = 0;
                }
            }
        }

        catch(Exception exception)
        {
            System.out.println("Ushh");
        }

    }

use '\r'

score 0 · Answer 3 · answered Jan 14 '22 at 08:52

Form feeds (the \u..C character) requires the terminal Emulator to do the clearing of the screen. This is common on Linux, but the standard one on Windows does not support this.

You may want to use an emulator that does. I believe the new Windows Terminal in the AppStore does.

Clearing Terminal Screen in Java

3 Answers3