How can i overcome this problem...in applet

Question

my applet will read in a file for data,
when i compile using JCreator, it work...
but when i open the html file to run, problems occur,
state that loading java applet failed.
the message shown in java console:
java.security.AccessControlException: access denied (java.io.FilePermission data.dat read)
     at java.security.AccessControlContext.checkPermission(Unknown Source)
     at java.security.AccessController.checkPermission(Unknown Source)
     at java.lang.SecurityManager.checkPermission(Unknown Source)
     at java.lang.SecurityManager.checkRead(Unknown Source)
     at java.io.FileInputStream.<init>(Unknown Source)
     at java.io.FileInputStream.<init>(Unknown Source)
     at java.io.FileReader.<init>(Unknown Source)
     at Reader.<init>(Reader.java:9)
     at Puzzle.init(Puzzle.java:30)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
thanks a lot for help

Answer 1

As I said, you need to read it from the server. Exactly how depends on what kind of data it is. If it's always going to be the same for the program then treat it as a "resource". If it's apt to change without rebuilding the program then serve it as a regular file, and access it via. a regular URL.
Say it's a resource, place it in the same directory as the .class file that loads it and do:
InputStream ds = getClass().getResourceAsStream("data.txt");
Reader r = new InputStreamReader(ds);
BuffererdReader br = new BufferedReader(r);