o in modo casuale????
codice:
 
public static boolean distribuzione(String file, String appoggio1, String appoggio2) throws FileNotFoundException {

Scanner in = new Scanner (new File(file));
PrintStream out1 = new PrintStream( newFile(appoggio1));
PrintStream out2 = new PrintStream( newFile(appoggio2));

PrintStream current = out1;
boolean swap = false;

Auto a = Auto.read(in);
if (a!=null){
a.print(current);
Auto ultimaInserita = a;

a = Auto.read(in);
while (a != null) {
if (a.compareTo(ultimaInserita)<0) {
if (current == out1) current = out2;
else current = out1;
swap = true;
}

a.print(current);
ultimaInserita = a;
a=Auto.read(in);
}
}
return !swap;

}