Remove all special characters from a phone number string entry except + occurring only at first place

You can use something like:

String number = "+91+1234#1234"
number=number.replaceAll("[\\D]", "")

This will replace all non digit characters with space but then for your additional "+" in the beginning ,you may need to add it as a prefix to the result.

Hope this helps!

The best way is to use regular expression:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main
{
    public static void main(String[] args)
    {
    String sPhoneNumber = "+911234567890";

    Pattern pattern = Pattern.compile("^[+]\\d*");
    Matcher matcher = pattern.matcher(sPhoneNumber);

    if (matcher.matches()) {
        System.out.println("Phone Number Valid");
    } else {
        System.out.println("Phone Number must start from  + ");
    }
 }
}

Scanner scan=new Scanner(System.in);
        String input=scan.next();
        String onlyDigits = input.replaceAll("[^0-9]+","");
        System.out.println(onlyDigits);