import java.io.*;
public class test {
public static void main(String[] args)throws IOException ,FileNotFoundException {
File data = new File("F:\\test.txt");
if (data.exists()) {
System.out.print("File already exists");
System.exit(0);
}
PrintWriter datas = new PrintWriter (data);
final int NUMBER_OF_DATAS_PER_LINE = 4 ;
for (int i = 0; i < 10; i++){
int j = (int) (Math.random()*20);
if ( (i+1) % NUMBER_OF_DATAS_PER_LINE == 0)
datas.println(j);
else
datas.print(j + " ");
}