I want to get the next incremented value of 9 (which is 10 of course) but it returns an ASCII code
<p>I was working on a property file. On it, I have an key which is "user_email" and the value, I set it to <strong>toomeuser0@gmail.com</strong>. </p>

<p>Now, in my code, I want the email value to iterate whenever my program runs, so toomeuser0@gmail.com will be toomeuser1@gmail.com and so on and from there, I read the email value in the property file and call it in my program.</p>

<pre><code> public String getEmailFromProperty(){

        String new_email = "";

        try{

            new ConfigReader();
            FileOutputStream fos = new FileOutputStream(property_file);
            StringBuilder str = new StringBuilder(property.getProperty("user_email"));

            char charWithNumber = str.charAt(9); // get the number character of the email (starts with 0)

            int toInteger = (int) charWithNumber; // convert that character number to an Integer value

            int numericValue = Character.getNumericValue(toInteger+1); // the number character in email is converted to int then incremented by 1 on each run

            int toAscii = numericValue + 48; // the number character (which is now an Int) is added by 48

            char toChar = (char) toAscii; // it is converted back to a character in order for it to be passed as a parameter to setCharAt() method

            str.setCharAt(9, toChar); // attached the newly incremented number character to the email @ 9th index

            new_email = str.toString(); // converted the StringBuilder variable str to an ordinary String in order to call toString() method

            property.setProperty("user_email", new_email); // now, I wrote the new email to the property file using the "user_email" key


            property.store(fos, null);
            fos.close();


        }
        catch(Exception e){
            System.out.println("Error is " + e.getMessage());

        }

        return new_email;


    }
</code></pre>

<p>I know this is kinda messy for you. But when the email number character reaches to value 9 and then it increments, I expected it to be 10. However, it returns '/' character. What I want after the run is <strong>toomeuser10@gmail.com</strong> NOT <strong>toomeuser/@gmail.com</strong></p>