I need to create an instance of a class that writes a file. I am
getting this exception:

basic: Stopping applet ...
basic: Removed progress listener:
sun.plugin.util.GrayBoxPainter@1157f77
basic: Finding information ...
basic: Releasing classloader: sun.plugin.ClassLoaderInfo@170888e,
refcount=0
basic: Caching classloader: sun.plugin.ClassLoaderInfo@170888e
basic: Current classloader cache size: 1
basic: Done ...
basic: Joining applet thread ...
basic: Destroying applet ...
basic: Disposing applet ...
basic: Quiting applet ...
basic: Joined applet thread ...
basic: Unregistered modality listener
basic: Registered modality listener
basic: Referencing classloader: sun.plugin.ClassLoaderInfo@170888e,
refcount=1
basic: Added progress listener: sun.plugin.util.GrayBoxPainter@a6faa9
basic: Loading applet ...
basic: Initializing applet ...
basic: Starting applet ...
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 DataAccess.load(DataAccess.java:11)
    at AddressBook32.<init>(AddressBook32.java:35)
    at Z115.init(Z115.java:107)
    at sun.applet.AppletPanel.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
basic: Exception: java.security.AccessControlException: access denied
(java.io.FilePermission data.dat read)
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 DataAccess.load(DataAccess.java:11)
    at AddressBook32.<init>(AddressBook32.java:35)
    at Z115.init(Z115.java:107)
    at sun.applet.AppletPanel.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
basic: Modality pushed
basic: Modality popped
Exception in thread "thread applet-Z115.class"
java.lang.NullPointerException
    at sun.plugin.util.GrayBoxPainter.showLoadingError(Unknown Source)
    at sun.plugin.AppletViewer.showAppletException(Unknown Source)
    at sun.applet.AppletPanel.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

I need to combat this exception. How do I do this?

Thanks.