Java System setIn() Method

The setIn() method of Java System class is used to reassign the "standard" input stream.

Syntax

Parameter

in - It is the new standard input stream.

Exception

SecurityException: This exception will throw if the security manager exists and its checkPermission method doesn't allow reassigning of the standard input stream.

Example

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class SystemSetInExample1 {
	public static void main(String[] args) throws IOException {
		File f= new File("abc.txt");
		System.out.println("file exist = "+f.exists());
		InputStream i=new FileInputStream(f);
		System.setIn(i);
		System.out.println("OK");
	}
}

Output: