Passando pelo Proxy

import java.io.*;
import java.net.*;
import sun.misc.BASE64Encoder; 

public class PassProxy {

  public PassProxy(String proxyhost, String proxyport, String proxylogin,  String proxypass, String url) {

	/* Set the proxy server host and port */
	System.setProperty("http.proxyHost", proxyhost);
	System.setProperty("http.proxyPort", proxyport);

	/* Set up and encode the proxy credentials */
	String s = proxylogin + ":" + proxypass;
	String se = new BASE64Encoder().encodeBuffer(s.getBytes());

	try {
	  /* Create a HttpURLConnection Object and set the properties */
	  URL u = new URL(url);
	  HttpURLConnection uc = (HttpURLConnection) u.openConnection();
	  uc.setRequestProperty("Proxy-Authorization", "Basic " + se);
	  uc.connect();

	  /* Print the content of the url to the console. */
	  showContent(uc);
	} catch (IOException e) {
	  e.printStackTrace();
	}
  }

  private void showContent(HttpURLConnection uc) throws IOException {
	InputStream i = uc.getInputStream();
	char c;
	InputStreamReader isr = new InputStreamReader(i);
	BufferedReader br = new BufferedReader(isr);
	String line;
	while ((line = br.readLine()) != null) {
	  System.out.println(line);
	}
  }

  public static void main(String[] args) {
	
	  String proxyhost = "xxxxxxx";
	  String proxyport = "80";
	  String proxylogin = "xxxx";
	  String proxypass = "xxxx";
	  String url = "http://www.guj.com.br";
	  new PassProxy(proxyhost, proxyport, proxylogin, proxypass, url);
	
  }

}

java.lang.IllegalArgumentException: Illegal character(s) in message header value: Basic U291emFNUjpub21pbmltbw==

	at sun.net.www.protocol.http.HttpURLConnection.checkMessageHeader(HttpURLConnection.java:171)
	at sun.net.www.protocol.http.HttpURLConnection.setRequestProperty(HttpURLConnection.java:1200)
	at PassProxy.<init>(PassProxy.java:26)
	at PassProxy.main(PassProxy.java:54)