modifying java.lang.String.java

Hi,
 I'm trying to modify java.lang.String.java and add the modified
String.class to
rt.jar [THIS IS FOR MYSELF ONLY AND WILL NOT BE DEPLOYED].
I cannot add "private final boolean tainted[] = new
boolean[5];" to String.java. If I do, it still compiles and I can add
it to rt.jar and compile a test program against it. However, the JVM
crashes with a strange message:

 java.lang.IllegalArgumentException: name can't be empty
       at java.security.BasicPermission.init(Unknown Source)
       at java.security.BasicPermission.<init>(Unknown Source)
       at java.lang.RuntimePermission.<init>(Unknown Source)
       at java.lang.Thread.<clinit>(Unknown Source)

I tried various ways of rewriting the above such as adding "private
final boolean tainted[];" and initializing it in each constructor.
Nothing works.


I can add methods to String.java and even the member variable "private
boolean isTainted;" and it works just fine. Do you have any ideas for
why adding a boolean array does not work (or better yet how to get
around this issue)?


Thank you,

Daniel