How to Clear Console in Java?

Question

I have been pulling my hair for this since quite long time. I have researched for an hour on how to clear a console in Java.

All I found was dirty hacking either by printing a bunch of lines or executing this

Runtime.getruntime.exec("cls/clear");

However, nothing seems to be working for me. Isn't there really any a way of clearing the console in Java like in C (clrscr();). Isn't there any external library by which this can be achieved.

Please let me know if anyone has ever done this before using a proper function, library etc. instead of dirty hacking.

Answer 1

If your terminal supports ANSI escape codes, this clears the screen and moves the cursor to the first row, first column:

System.out.print("\033[H\033[2J");
System.out.flush();

This works on almost all UNIX terminals and terminal emulators. The Windows cmd.exe does not interprete ANSI escape codes.

Answer 2

Try this code

import java.io.IOException;

public class CLS {
    public static void main(String... arg) throws IOException, InterruptedException {
        new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
    }
}

Now when the Java process is connected to a console, it will clear the console.

Answer 3

Runtime.getRuntime().exec("PlatformDepedentCode");

You need to replace "PlatformDependentCode" with your platform's clear console command.

The exec() method executes the command you entered as the argument, just as if it is entered in the console.

In Windows you would write it as Runtime.getRuntime().exec("cls");.

Answer 4

Use the following code:

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System.out.println("\f");

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'\f' is an escape sequence which represents FormFeed. This is what I have used in my projects to clear the console. This is simpler than the other codes, I guess.

Answer 5

You need to instruct the console to clear.

For serial terminals this was typically done through so called "escape sequences", where notably the vt100 set has become very commonly supported (and its close ANSI-cousin).

Windows has traditionally not supported such sequences "out-of-the-box" but relied on API-calls to do these things. For DOS-based versions of Windows, however, the ANSI.SYS driver could be installed to provide such support.

So if you are under Windows, you need to interact with the appropriate Windows API. I do not believe the standard Java runtime library contains code to do so.

Answer 6

You can easily implement clrscr() using simple for loop printing "\b".

Answer 7

If you are using windows and are interested in clearing the screen before running the program, you can compile the file call it from a .bat file. for example:

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cls

java "what ever the name of the compiles class is"

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Save as "etc".bat and then running by calling it in the command prompt or double clicking the file