Add minutes to current date in java

I have a problem when it comes to obtaining a new date in the calendar after adding a few minutes to the current one.

I start getting the current date:

java.util.Date fechaActual = new java.util.Date();

By means of a function that I have created and that receives 4 parameters (Current date, days, hours and minutes), I want to calculate the new date. For this I do this:

Date nueva_fecha = sumarDiasAFecha(fechaActual, days, hours, minutes);

public static Date sumarDiasAFecha(Date fecha, int dias, int horas, int minutos){                       

            if (dias==0 && horas==0 && minutos==0) {
                return fecha;
            }


            Calendar calendar = Calendar.getInstance();
            calendar.setTime(fecha); 

            //pasamos todo a minutos

            int total_minutos = (dias*24*60) + (60*horas) + minutos;

            calendar.add(Calendar.MINUTE, total_minutos);
            return calendar.getTime(); 
        }

Later I pass the date from Date to Calendar and work with it to get a date:

Calendar fecha_calendar = DateToCalendar(nueva_fecha);

int anyo = fecha_calendar.get(Calendar.YEAR);
int mes = fecha_calendar.get(Calendar.MONTH) + 1;
int dia = fecha_calendar.get(Calendar.DAY_OF_MONTH);
int hour = fecha_calendar.get(Calendar.HOUR);
int minute = fecha_calendar.get(Calendar.MINUTE);

String mes_fecha = "";
if (mes < 10) {
     mes_fecha = "0"+mes;
} else {
     mes_fecha = String.valueOf(mes);
}

 String dia_fecha = "";
 if (dia < 10) {
       dia_fecha = "0"+dia;
 } else {
       dia_fecha = String.valueOf(dia);
 }

 String hour_fecha = "";
 if (hour < 10) {
       hour_fecha = "0"+hour;
 } else {
       hour_fecha = String.valueOf(hour);
 }

 String hour_minute = "";
 if (minute < 10) {
       hour_minute = "0"+minute;
 } else {
       hour_minute = String.valueOf(minute);
 }

 String fecha_total = String.valueOf(anyo) + "-" + mes_fecha + "-" + dia_fecha + " " + hour_fecha + ":" + hour_minute + ":00";

The code works for me the year and month, but the hours do not, and I do not understand why.