hmm.. what version of netbeans are you using? it works for me in the
dev build 200206030100. I think I've done some fixes that deal with
the issue in the 3.4 codebase.

please try to modify the Netbeans/bin/ide.policy file grant all
permissions to everyone

grant codeBase "file:/-" {
   permission java.security.AllPermission;
};

I'm sorry, I've tried the example with Beanshell, rather than dynamic
java.. it doesn't work for me either..
I've searched the history of bugs and I think your problme is a
duplicate of #19133.

please add the switch -J-Dnetbeans.security.nocheck=true to your
ide.cfg file and it should work, however there's more to the problem
of DynamicJava, for details and how to workaround the problme see #19133

*** This issue has been marked as a duplicate of 19133 ***

Thanks for your answer and the hint to issue 19133. 

Your analysis given there of the exception appearing after
-J-Dnetbeans.security.nocheck=true has been added to ide.cfg is clear
and corresponds to my own thoughts. But the first exception reported
in issue 19133 seems strange to me.  It appears when
-J-Dnetbeans.security.nocheck=true is not added to ide.cfg. It is
identical to the exception I reported in this issue.

This exception is thrown because access is denied to create a new
class loader.

Why is access denied to create a new class loader ? The ide.policy
explicitely provides all
permissions to all local files and also the TopSecurityManager does
not disallow class loader creation.  So why this problem ?

The answer seems to be that an entry like

grant codeBase "file:/-" {
      permission java.security.AllPermission;
   };

seems not to be sufficient. If I try:

grant {
    permissions java.lang.RuntimePermission "createClassLoader";
  };

grant codeBase "file:/-" {
      permission whatever-appropriate;
   };

the first exception does not appear and I get the second one. Hence it
is not necessary to add -J-Dnetbeans.security.nocheck=true to ide.cfg.
It suffices to add

grant {
    permissions java.lang.RuntimePermission "createClassLoader";
};

to the policy file. This allows all classes, not only those retrieved
from a local file but also dynamically generated ones to create a
class loader.

Unfortunately this permission is quite heavy and one would like to add
it only to the classes created by the DynamicJava interpreter. Is it
possible to add the `createClassLoader' permission
only to DynamicJava generated classes ?

Thanks for the analysis, Holger. I must admit I don't have deep
knowledge of security managers, I've CCed people that could answer
your questions. 

Jesse I wonder if that's worth the fix in ide.cfg..

I think this is a clear duplicate of #19133, right? where the details
are covered nicely.

Adding general permission to create new classloaders to ide.cfg is
unacceptable for security reasons, and should not be necessary if
#19133 is fixed properly.

Hi Jesse,

yes it is a duplicate of  #19133. I added a DynamicJava patch to
#19133 which, if applied to DynamicJava, would solve the problems
without compromising security at all.

Holger

Resolved for 3.4.x or earlier, no new info since then -> closing.

Resolved for 3.4.x or earlier, no new info since then -> closing.