Java doesn't pick up system's DNS settings change until restarted

package com.test.dnsresolver;

import java.io.BufferedReader;

public class DnsResolver {
	private static final String urlString = "www.google.com";
	private static final String resolvConf = "/etc/resolv.conf";

	public static void main(String[] args) {

		int loopCounter = 0;
		while (true) {
			loopCounter++;
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {}

			// Parse the current DNS server to be used in the config
			String nameserver = null;
			try {
				BufferedReader input =  new BufferedReader(new FileReader(new File(resolvConf)));
				String currentLine = null;
				while (( currentLine = input.readLine()) != null){
					// Take care of potential comments
					currentLine = currentLine.substring(0, currentLine.indexOf("#") == -1
							? currentLine.length() : currentLine.indexOf("#") );

					if (currentLine.contains("nameserver")) {
						// It is the line we are looking for
						nameserver = currentLine;
						break;
					}
				}
			} catch (FileNotFoundException e) {
				System.out.println("Loop " + loopCounter + ": FileNotFoundException");
			} catch (IOException e) {
				System.out.println("Loop " + loopCounter + ": IOException");
			}

			if (nameserver == null) {
				// No "nameserver" line found
				System.out.println("Loop " + loopCounter + ": No nameserver found in configration file!");
				continue;
			}
			
			// Trim it to just contain the IP address
			nameserver = (nameserver.replace("nameserver", "")).trim();
			System.out.println("Loop " + loopCounter + ": Going to use DNS server " + nameserver);

			// At this point, we know which server to use, now perform the resolution
			Hashtable<String, String> env = new Hashtable<String, String>();
			env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
			env.put("java.naming.provider.url",    "dns://" + nameserver);

			DirContext ictx;
			try {
				ictx = new InitialDirContext(env);
				Attributes attrs1 = ictx.getAttributes(urlString, new String[] {"A"});
				System.out.println("Loop " + loopCounter + ": Manual resolution: +" + attrs1.get("a").get() + "+");

			} catch (NamingException e) {
				System.out.println("Loop " + loopCounter + ": NamingException");
			}
		}
	}
}