import java.io.*;

public class RecordatorioFicheros{
    public static void main(String args[]){
        try{
            FileReader fr=new FileReader("prueba.txt");
            BufferedReader br=new BufferedReader(fr);
            String leido=br.readLine();
            while(leido!=null){
                System.out.println(leido);
                leido=br.readLine();
            }
            br.close();
            fr.close();
            // Ahora lo reescribimos true=append, false-defecto=writer
            FileWriter fw=new FileWriter("prueba.txt",true);
            BufferedWriter bw=new BufferedWriter(fw);
            bw.write("Otra linea"+"\r\n");
            bw.close();
            fw.close();
        }catch(Exception e){
        }
    }
}