FULL PRODUCT VERSION :
java version "1.6.0_11"
Java(TM) SE Runtime Environment (build 1.6.0_11-b03)
Java HotSpot(TM) Client VM (build 11.0-b16, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
JApplet throw exception in JDK 1.6 update 11, but working in JDK 1.6 update 10


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Java Plug-in 1.6.0_11
Using JRE version 1.6.0_11 Java HotSpot(TM) Client VM
User home directory = C:\Documents and Settings\MethoD
----------------------------------------------------
c:   clear console window
f:   finalize objects on finalization queue
g:   garbage collect
h:   display this help message
l:   dump classloader list
m:   print memory usage
o:   trigger logging
q:   hide console
r:   reload policy configuration
s:   dump system and deployment properties
t:   dump thread list
v:   dump thread stack
x:   clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------


---->uk.ac.leeds.ccg.geotools.MouseStatus constructed. Will be identified as MoS->
---->uk.ac.leeds.ccg.widgets.ZoomLevelPicker constructed. Will identify itself as ZLP->
---->uk.ac.leeds.ccg.widgets.ThemePanel constructed. Will identify itself as ThP->
Thp->setThemes
Thp->Setting background: java.awt.Color[r=255,g=255,b=255]
Thp->Setting foreground: java.awt.Color[r=0,g=0,b=0]
reading maps/aim_tov
SfR->General exception in zip read
SfR->java.security.AccessControlException: access denied (java.io.FilePermission C:\Documents and Settings\All Users\Documents\applet\maps\aim_tov.shp read)
java.lang.NullPointerException
	at uk.ac.leeds.ccg.geotools.ShapefileReader.guessIdCol(ShapefileReader.java:291)
	at uk.ac.leeds.ccg.geotools.ShapefileReader.<init>(ShapefileReader.java:286)
	at Location.loadMaps(Location.java:91)
	at Location.start(Location.java:145)
	at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Exception: java.lang.NullPointerException

REPRODUCIBILITY :
This bug can be reproduced always.

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Attached seperatly
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Release Regression From : 6u10
The above release value was the last known release where this 
bug was not reproducible. Since then there has been a regression.