Find recurring character in a string ( the first character of the string)

[xgiovio]

public class test {

    public static void main (String [] input_data){

        String dato =  input_data[0];
        char first_letter = dato.charAt(0);
        int i, position;


                for (i=1; i < (dato.length()) ;){

                    position = dato.indexOf(first_letter ,i) ;

                    if (position == -1) {
                        break;
                    }else{
                        System.out.print("Posizione ripetuta:") ;
                        System.out.print(position) ;
                        System.out.print("\n") ;
                        i= position + 1;
                    }

                }



    }
}