UPDATED: 05 December 2011

Sample code to get IP address

request.getHeader("VIA");
String ipAddress = request.getHeader("X-FORWARDED-FOR");
       if (ipAddress == null) {
            ipAddress = request.getRemoteAddr();
       }

This code works perfectly i tested it on my server. Now you have IP address but after that question is how to get Country, City, Latitude, Longitude using Java? This will be done by javaQuery API. For that u can try below code.

Important notice for existing user (javaQueryAPI 7.0 or less) : Please check the new changes in javaQueryAPI 8.0 before installing API in your project.

/*
* javaQueryAPI 7.0 or less
*/
import javaQuery.j2ee.GeoLocation
request.getHeader("VIA");
String ipAddress = request.getHeader("X-FORWARDED-FOR");
       if (ipAddress == null) {
            ipAddress = request.getRemoteAddr();
       }
GeoLocation gl = new GeoLocation();
gl.GetGeoLocationByIP(ipAddress);
String country = gl.Country;

/*
* javaQueryAPI 8.0 or above
*/
import javaQuery.importClass.javaQueryBundle;
import javaQuery.j2ee.GeoLocation;

request.getHeader("VIA");
String ipAddress = request.getHeader("X-FORWARDED-FOR");
       if (ipAddress == null) {
            ipAddress = request.getRemoteAddr();
       }
        GeoLocation $gl = javaQueryBundle.createGeoLocation();
        $gl.MAPTargetByIP("117.204.232.104", "This is Demo. You can set even NULL");
        System.out.println($gl.Latitude);
        System.out.println($gl.Longitude);
        System.out.println($gl.Country);
        System.out.println($gl.City);
        System.out.println($gl.State);
        System.out.println($gl.GoogleMap_URL);
        System.out.println($gl.GoogleMap_URL_Bubble);
   
/*
* output
* 23.0333
* 72.616699
* India
* Ahmedabad
* Gujarat
* http://maps.google.com/maps?q=23.0333,+72.616699+(117.204.232.104)&iwloc=A&hl=en
* http://maps.google.com/maps?q=23.0333,+72.616699+(This is Demo. You can set even NULL)&iwloc=A&hl=en
*/