Java - How to get permission in Java Web Start

Hi managed to create the jar and .jnlp files for my Java application but running into trouble when it runs. Launches okay with Java Web Start but I think I need to do something extra as normally when I run it it doesn't ask for permission to access the HD for file I/O. Would appreciate some help and advise to know what to do to get the permission rights i.e. what do I have to do is it something I have to do to all my classes not sure. The error message I get in Java Web Start is as below. ``` Exception in thread "AWT-EventQueue-0" java.security.AccessControlException: access denied (java.io.FilePermission StockDatabase;Stocks.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.File.exists(Unknown Source) at StockCodeDatabase.<init>(OptraderSA.java:782) at OptraderSA.actionPerformed(OptraderSA.java:136) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.AbstractButton.doClick(Unknown Source) at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source) at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unkno ```