Sortowanie liczb z pliku

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
public class glowna {
	//Sortowanie liczb z pliku i zapisywanie do drugiego.
        public static void main(String[] args) {
                try {
                		File pliko = new File("output.txt");
                		pliko.createNewFile();
                        BufferedReader  strum1 = new BufferedReader(new FileReader("input.txt"));
                        String liczba;
                        int i=0;
                        int tab[] = new int[100];
                        while((liczba = strum1.readLine())!=null)
                        {
                                tab[i] =Integer.parseInt(liczba);
                                System.out.println(liczba);
                                i++;
                        }
                        strum1.close();
                        Arrays.sort(tab);
                        BufferedWriter strum2 = new BufferedWriter(new FileWriter("output.txt"));
                        for(int a=0;a<100;a++)
                        {
                                strum2.write(Integer.toString(tab[a]));
                                strum2.newLine();
                        }
                        strum2.close();
                } catch (FileNotFoundException e) {
                        e.printStackTrace();
                } catch (IOException e) {
                        e.printStackTrace();
                }
        }
}