Postal code checker.

gistfile1.java

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

public class Program
{
    public String test(String postalCode)
    {
        Pattern nan = Pattern.compile("\\d[A-Z]\\d");
        Pattern ana = Pattern.compile("[A-Z]\\d[A-Z]");
        Matcher mNan = nan.matcher(postalCode);
        Matcher mAna = ana.matcher(postalCode);
        if (mNan.find() || mAna.find()){ 
            return "OK";
        } else {
            return "ERROR";
        }        
    }
}