Validating IPv4 string in Java

Question

Bellow method is validating if string is correct IPv4 address it returns true if it is valid. Any improvements in regex and elegance would be very appreciated:

public static boolean validIP(String ip) {     if (ip == null || ip.isEmpty()) return false;     ip = ip.trim();     if ((ip.length() < 6) & (ip.length() > 15)) return false;      try {         Pattern pattern = Pattern.compile("^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$");         Matcher matcher = pattern.matcher(ip);         return matcher.matches();     } catch (PatternSyntaxException ex) {         return false;     } } 

Answer 1

Here is an easier-to-read, slightly less efficient, way you could go about it.

public static boolean validIP (String ip) {     try {         if ( ip == null || ip.isEmpty() ) {             return false;         }          String[] parts = ip.split( "\\." );         if ( parts.length != 4 ) {             return false;         }          for ( String s : parts ) {             int i = Integer.parseInt( s );             if ( (i < 0) || (i > 255) ) {                 return false;             }         }         if ( ip.endsWith(".") ) {             return false;         }          return true;     } catch (NumberFormatException nfe) {         return false;     } }