Pattern matching for validating the input

I have to validate the input as

• Asterisks are permitted in positions 2-5.
• Position One should be alphabetic (except for the ~) -No characters should accept numbers.
• Other than the exceptions mentioned above, no special characters are allowed

I am trying to build as this.

final Pattern pattern =
            Pattern.compile("^[a-zA-Z~][a-zA-Z*]*$", Pattern.CASE_INSENSITIVE);

final Matcher matcher = pattern.matcher(this.mainStaOrgBO.getStaOrgCode());
        final boolean specialCharCheck = matcher.find();
        if (specialCharCheck) {
}

How about:

^[a-zA-Z~][a-zA-Z*]{1,4}[a-zA-Z]*$

Explanation:

^                   : start of string
    [a-zA-Z~]       : First char can be letter or ~
    [a-zA-Z*]{1,4}  : char 2 to 5 can be letter or *
    [a-zA-Z]*       : rest of string only letter
$                   : end of string.