public Date compareDate(Date Kred_Deb_Date, Date Book_Date){
    Date date1 = null;
    if (Book_Date.compareTo(Kred_Deb_Date)<0){
        date1 = get_book_date();
        compareDate(Kred_Deb_Date, date1);
    }else if (Book_Date.compareTo(Kred_Deb_Date)>0){
        date1 = Book_Date;
        return date1;
    }
}

if (Book_Date.compareTo(Kred_Deb_Date)<0){
    date1 = get_book_date();
    compareDate(Kred_Deb_Date, date1);
}else if (Book_Date.compareTo(Kred_Deb_Date)>0){
    date1 = Book_Date;
    return date1;
}else{
    return ...
}

public Date compareDate(Date Kred_Deb_Date, Date Book_Date){
    Date date1 = null;
    if (Book_Date.compareTo(Kred_Deb_Date)<0){
        date1 = get_book_date();
        compareDate(Kred_Deb_Date, date1);
    }else if (Book_Date.compareTo(Kred_Deb_Date)>0){
        date1 = Book_Date;

    }
        return date1;
}