Re: File creation Problem

[dawall@xxxxxxxxxx]

By default, browsers do not let applets write to the local file system.
This is good thing.  Think of the viruses you could write if they let you
at the disk.  Via a hidden applet you could write just about anything to
the PC and the user wouldn't even know it.

There are a lot of Java things you can't do from a browser but in some
cases the browser has a property to override the default.  In that case the
user gets a dialog asking if it is okay to do the action.  For example, if
the applet wants to make a socket connection to a server other than the
html server, it must override a property which causes a dialog the user
must answer.  I don't think file io can be overridden, however.  Anyone
know for sure?

David Wall
553-5329
AS/400 Toolbox for Java


"Padmanabhan R (RBIN/ACF)" <Padmanabhan.R@in.bosch.com> on 05/17/2000
10:29:40 AM

Please respond to JAVA400-L@midrange.com

To:   JAVA400-L@midrange.com
cc:
Subject:  File creation Problem




Hello ,

          I tried to run the following code , but it is throwing out
the security exception.

import java.applet.*;
import java.awt.*;
import java.io.*;

public class SimpleSaver extends Applet
{

     public void init()
     {
          Button b = new Button("Beans Book");
          b.setFont(new Font("System", Font.BOLD, 36));
          add(b);
          Saver f = new Saver(b);

     }


class Saver
{

public Saver(Button b){


     try{

               FileOutputStream f = new
FileOutputStream("Sav.tmp");
               ObjectOutput s = new ObjectOutputStream(f);
               s.writeObject(b);
               s.flush();
               }catch(Exception e)
                {
                    e.printStackTrace();
                    System.out.println(e);
               }


                    }

  }

}

Exception

E:\jdk1.2\bin\appletviewer.exe     SimpleApplet.html
Working Directory - E:\samples\
Class Path - E:\samples\;
;.;d:\Kawa\classes.zip;e:\jdk1.2\lib\tools.jar;e:\jdk1.2\jre\lib\rt.jar;E:\j

dk1.2\lib\dt.jar;E:\jdk1.2\jre\lib\jaws.jar;E:\jdk1.2\jre\lib\i18n.jar;E:\jd

k1.2\lib\servlet.jar;E:\jdk1.2\lib\as400Driver.jar;i:\proddata\http\public\j

t400\utilities\;i:\proddata\http\public\jt400\lib\jt400.jar
java.security.AccessControlException: access denied (java.io.FilePermission
Sav.tmp write)

     at java.security.AccessControlContext.checkPermission(Compiled Code)

     at java.security.AccessController.checkPermission(Compiled Code)

     at java.lang.SecurityManager.checkPermission(Compiled Code)

     at java.lang.SecurityManager.checkWrite(SecurityManager.java:946)

     at java.io.FileOutputStream.<init>(FileOutputStream.java:96)

     at java.io.FileOutputStream.<init>(FileOutputStream.java:62)

     at SimpleSaver$Saver.<init>(SimpleSaver.java:26)

     at SimpleSaver.init(SimpleSaver.java:13)

     at sun.applet.AppletPanel.run(Compiled Code)

     at java.lang.Thread.run(Thread.java:479)

java.security.AccessControlException: access denied (java.io.FilePermission
Sav.tmp write)

Process Exit...
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