I have a string for a Date in the form mm/dd, and I need to check if either the month or day was entered as a double

public Date(String dateStr){
        int slash = 0;

        //check slash is present
        try{
            slash = dateStr.indexOf('/');
        }catch(StringIndexOutOfBoundsException e){
            error = "Invalid date format: " + dateStr;
        }

        //check if month is a number
        try{
            month = Integer.parseInt(dateStr.substring(0, slash));
            //day = Integer.parseInt(dateStr.substring(slash + 1, dateStr.length()));
        }
        catch(NumberFormatException e){
            System.out.println("Invalid format for input string: " + dateStr.substring(0, slash));
        }

        //check if day is a number
        try{
           day = Integer.parseInt(dateStr.substring(slash + 1, dateStr.length()));
        }
        catch(NumberFormatException e){
            System.out.println("Invalid format for input string: " + dateStr.substring(slash + 1, dateStr.length()));
        }

        //check if month was entered as a double




    }