check hostname

gistfile1.java

import java.net.InetAddress;
import java.net.UnknownHostException;

public class dns {
    public static void main(String[] args) throws UnknownHostException {
        InetAddress addr = InetAddress.getLocalHost();

        System.out.println(String.format(
           "IP:%s hostname:%s canonicalName:%s",
                addr.getHostAddress(),
                addr.getHostName(),
                addr.getCanonicalHostName()
        ));
    }
}