Applet Security issue

**DanBrown** · January 25th, 2011, 07:59 AM

Hey Friends,

I have an issue in developing a applet whose purpose is to read xml file and show it in to applet.

For that purpose i was trying to write a program which contains an Text box and a XML read function which read xml file and then set content to Text box.

What i had done is:

I had created a jar file consisting of the following files

jar cfv MyAppletJar.jar DemoTest.class Company.xml

1) Applet class

import javax.swing.*;
import java.io.File;
import java.awt.*;
 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
 
 
public class DemoTest extends JApplet{	
 
 
	JTextField tf;
 
	public void init(){
 
		try {
            		tf = new JTextField(20);
					add(tf);
					System.out.println(DemoTest.createTestX("Company.xml"));
 
 
                 } catch (Exception e) { 
                                System.err.println("createGUI didn't complete successfully"+e);
                 }
 
	}
 
       public static  String createTestX(String filePath) {
 
            try {
                      File file = new File(filePath);
                      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
                      DocumentBuilder db = dbf.newDocumentBuilder();
                      Document doc = db.parse(file);
                     doc.getDocumentElement().normalize();
                      System.out.println("Root element " + doc.getDocumentElement().getNodeName());
                      NodeList nodeLst = doc.getElementsByTagName("employee");
                      System.out.println("Information of all employees");
                      return doc.getDocumentElement().getNodeName();
             } catch (Exception e) {
                      System.out.println("File Reading error");
                      e.printStackTrace();
        }
 
      return null;
 }
 
 
}

2) Xml file

 
<?xml version="1.0"?>
<company>
	<employee>
		<firstname>Tom</firstname>
		<lastname>Cruise</lastname>
	</employee>
	<employee>
		<firstname>Paul</firstname>
		<lastname>Enderson</lastname>
	</employee>
	<employee>
		<firstname>George</firstname>
		<lastname>Bush</lastname>
	</employee>
</company>

after this i had created an html page embed with applet tag to embed applet.

<HTML>
<Head>
<Title>Test XML </Title>
<Body>
 
<APPLET CODE="DemoTest.class" width="100" height="100" archive="MyAppletJar.jar">
</APPLET>
 
</Body>
</HTML>

But its throwing Java.security.accesscontrolException

I can understand the problem in reading file from client system , but the file is available within the same jar file in which applet class is available .

Now i m not getting what to do

Please help me out.

**KevinWorkman** · January 25th, 2011, 09:05 AM

Get your file this way instead: Finding and Loading Data Files (The Java™ Tutorials > Deployment > Applets)

**DanBrown** · January 25th, 2011, 09:27 AM

Sorry , i already gone through that tutorial but not getting any thing.

**KevinWorkman** · January 25th, 2011, 09:36 AM

What are you confused about? That tutorial contains example code that loads an image file. It shouldn't be too hard to extrapolate that to load any kind of file.

If you still aren't sure, then don't be afraid to print out or display the values returned by the methods (there aren't many) discussed in that tutorial.

**DanBrown** · February 4th, 2011, 07:03 AM

Error message while reading

java.security.AccessControlException: access denied (java.util.PropertyPermission user.dir read)

as i read in Code ranch i need to specify permissions to the applet.

can u please tell what permissions i need to write in policy files.

I had written one

grant {
 
  permission java.io.FilePermission 
	"message.xmlt", "read,write";
};

**copeg** · February 4th, 2011, 09:50 AM

Applets have security constraints when doing certain tasks. Sign the applet to remove these constraints. Here's a step by step example: How to sign an applet

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