How to Clear Screen in Java

In Java, when we compile and run Java programs, the console or screen gets messed up with lots of commands and output. To reduce or clear the messing content of the console, we need to clear the screen in Java so that we can execute programs in a proper way. In this section, we will learn how to clear the console or screen in Java.

There are the following ways to clear screen or console in Java:

Using ANSI escape Code
Using Platform Specific Command
Using Command Line Interpreter

Using ANSI Escape Code

ANSI escape sequence is standard in-band signaling to control the cursor position. In the following example, we have used the escape code \033[H\033[2J. Let's break the code and understand it separately.

\033: It represents the ASCII escape character. Its ANSI value is 27. It stands for ESC.
[: It represents the escape sequence. It is also known as CSI (Control Sequence Indicator). The CSI command starts with ESC[ followed by zero or more parameters.

On combining the above codes, we get \033[ or ESC[.

\033[H: It moves the cursor at the top left corner of the screen or console.
\033[2J: It clears the screen from the cursor to the end of the screen.

Let's combine the above two codes, we get \033[H\033[2J. The combination of code clears the screen or console.

The CSI commands use the default values if we do not specify any parameter in the command. We can use the following code to clear the screen in Java:

ClearScreenExample1.java

public class ClearScreenExample1
{
public static void main(String[] args)
{
System.out.print("\033[H\033[2J");
System.out.flush();
}
}

In the above example, we have used the same code (\033[H\033[2J) that we have explained above. It clears the console. We have also used the flush() function that resets the cursor position at the top of the screen.

Using Platform-Specific Command

We can also use the command according to the platform we are using. In this method, first, we get the property of the system by using the getProperty() method of the System class. After that, we select the command used in the platform to clear the console.

System.getProperty() Method

It is the static method of the System class. It is used to get the system property indicated by the specified key. It parses a parameter key of type String. It specifies the name of the system property. It returns the property of the system and

Syntax:

It throws the following exceptions:

SecurityException: If there exists a security manager and its checkPropertyAccess() method does not allow access to the specified system property.
NullPointerException: It throws the exception if we do not specify the key null.
IllegalArgumentException: It throws the exception if the key is empty.

Let's create a Java program that clears the console using the platform-specific command.

ClearScreenExample2.java

public class ClearScreenExample2
{
public final static void clearConsole()
{
public static void main(String[] args)
{
try
{
final String os = System.getProperty("os.name");
if (os.contains("Windows"))
{
Runtime.getRuntime().exec("cls");
}
}
catch (final Exception e)
{
e.printStackTrace();
}
}

In the above example, we have specified the Windows operating system and the command that is used to clear the console is cls. We can also use the following code in the above program:

public final static void clearConsole()
{
try
{
final String os = System.getProperty("os.name");
if (os.contains("Windows"))
{
Runtime.getRuntime().exec("cls");
}
else
{
Runtime.getRuntime().exec("clear");
}
}
catch (final Exception e)
{
e.printStackTrace();
}
}

Using Command Line Interpreter

In this method, we invoke the command line interpreter (CMD). After invoking the interpreter executes the cls command. It allows executing the built-in commands. Now we need to connect the interpreter output channel with the Java process output channel. It can be done by using the inheritIO() method.

ClearScreenExample3.java

import java.io.IOException;
public class ClearScreenExample3
{
public static void main(String... arg) throws IOException, InterruptedException 
{
new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
}
}

Once the above program connects with the console, it starts from a command line without output redirection and clears the screen or console.

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