HTTP in Java

Question

Hi, I am **very** new to Java, though I have prior knowledge of C, C++, Pascal, LISP, etc.
I was trying to write a program to simply fetch the first character of a text file from the web, in order to test my knowledge of HTTP in Java. The document is shed.hawknetwork.org/gamefiles/test.txt, which contains simply the content "thisisatest".
Here is what I wrote. It doesn't really work at all, and I was hoping someone would give me a hand in fixing it. I also attach the error given by Java, which doesn't make any sense to me as I am so new to the language.
Thanks in advance,
Adam.
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import java.applet.*;
public class TestApp extends Applet implements ActionListener
Button Test;
public void init()
  setLayout(new FlowLayout());
  Test = new Button("Test");
  Test.addActionListener(this);
  add(Test);
public void stop()
public char GetFirstChar()
  URL u;
  InputStream in;
  int c;
  try
   u = new URL("http://shed.hawknetwork.org/gamefiles/test.txt");
  catch(MalformedURLException e)
   getAppletContext().showStatus("Error 1.");
   return ' ';
  try
   in = u.openStream();
  catch(IOException e)
   getAppletContext().showStatus("Error 2.");
   return ' ';
  try
   c = in.read();
  catch(IOException e)
   getAppletContext().showStatus("Error 3.");
   return ' ';
  return ((char) c);
public void actionPerformed(ActionEvent act)
  char c;
  if (act.getSource() == Test)
   c = GetFirstChar();
   if (c != ' ')
    showStatus(String.valueOf(GetFirstChar()));
Exception in thread "AWT-EventQueue-1" java.security.AccessControlException: acc
ess denied (java.net.SocketPermission shed.hawknetwork.org:80 connect,resolve)
at java.security.AccessControlContext.checkPermission(AccessControlConte
xt.java:264)
at java.security.AccessController.checkPermission(AccessController.java:
427)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
at java.lang.SecurityManager.checkConnect(SecurityManager.java:1034)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:459)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:214)
at sun.net.www.http.HttpClient.New(HttpClient.java:287)
at sun.net.www.http.HttpClient.New(HttpClient.java:299)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLC
onnection.java:795)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConne
ction.java:747)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection
.java:672)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLCon
nection.java:916)
at java.net.URL.openStream(URL.java:1007)
at TestApp.GetFirstChar(TestApp.java:41)
at TestApp.actionPerformed(TestApp.java:68)
at java.awt.Button.processActionEvent(Button.java:388)
at java.awt.Button.processEvent(Button.java:356)
at java.awt.Component.dispatchEventImpl(Component.java:3955)
at java.awt.Component.dispatchEvent(Component.java:3803)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchTh
read.java:242)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre
ad.java:163)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

Answer 1

Maybe you can with Java Web Start. I don't know. If it's a requirement that you start it from a web page, a standalone app probably isn't what you want.
I'd suggest changing your applet so that it doesn't hardcode the URL it's trying to retrieve in the applet. Use a relative URL. So for example use resources references:
http://java.sun.com/j2se/1.5.0/docs/guide/lang/resources.html
Or create the URL dynamically by doing Applet.getCodeBase or .getDocumentBase and then futzing with the URL.
And/or put the applet and html on the server you're trying to reach from the applet.
The first option is probably best.