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POSelf-signed Applet throws SecurityException when writing to file
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  1. POSelf-signed Applet throws SecurityException when writing to file
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    copied!<p>I want to make an Applet that's capable of downloading files to a computer, and then opening them in the associated editor (when the file is saved, it is supposed to be uploaded back again). However, before I spend hours getting it to work, I have to make sure that it is actually manageable (Have done it with a Java Desktop Application just not an Applet).</p> <p>So I wrote a simple applet that creates a file if it doesn't exist. The app is <strong>signed</strong> and loads in the browser as it should. The following is written to the screen:</p> <blockquote> <p>IO Exception: Access is denied</p> </blockquote> <p>I have labeled the different errors, so I know which one that fails. Below is my applet:</p> <pre><code>import javax.swing.*; import java.security.*; import java.io.*; public class DocumentApplet extends JApplet { private static final long serialVersionUID = -2354727776089972258L; public void start () { add ( new JButton ("Hello, World") ); AccessControlContext acc = (AccessControlContext) System.getSecurityManager().getSecurityContext(); try { acc.checkPermission(new FilePermission("test.txt", "write")); } catch (SecurityException e) { add (new JLabel ("Permission Exception: " + e.getMessage())); return; } try { File f = AccessController.&lt;File&gt;doPrivileged(new PrivilegedAction&lt;File&gt;() { public File run() { return new File ("test.txt"); } }); if ( ! f.exists()) { f.createNewFile(); } } catch (AccessControlException e) { add (new JLabel ("Access: " + e.getMessage())); } catch (IOException e) { add ( new JLabel ("IO Exception: " + e.getMessage())); } } } </code></pre> <p>It is the last exception that is being thrown. Note that the first thing I do, is to check permissions. That check does not fail.</p> <p>The Applet is self-signed, but this is only temporary. <strong><em>I do not want to spend hundreds of dollars in buying a certificate, if the applet is failing..</em></strong>.</p> <p>When I run the app with <em>appletviewer</em>, the code works. That's OK, but I need to know that it will work when I buy a real certificate.</p> <p>HTML Code:</p> <pre><code>&lt;applet code="DocumentApplet" archive="applet.jar" width="300" height="200"&gt; &lt;/applet&gt; </code></pre> <p>Environment: Windows7 + JDK 1.7.0_05</p> <p>PS: I have also spent the last two days reading on Stackoverflow and searching Google. I strongly believe I have done everything I am supposed to do...</p>
 

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