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class ACC {

  private static class RestrictedAccessControlContext {
      private static final AccessControlContext INSTANCE;
      static {	      
          INSTANCE = new AccessControlContext(new ProtectionDomain[] {
                  new ProtectionDomain(null, null) // no permissions
              });
      }
  }

  // First sanitize firstName (modify if the name may include special characters)

  if(!firstName.matches("[\\w]*")) { // String does not match whitelisted characters
    throw new IllegalArgumentException();
  } 

  // Restrict permission using the two-argument form of doPrivileged()
  try {
    AccessController.doPrivileged(new PrivilegedExceptionAction() {
      public Object run() throws ScriptException {
        engine.eval("print('"+ firstName + "')");		
        return null;
      }    	
    }, RestrictedAccessControlContext.INSTANCE); // From nested class
  } catch(PrivilegedActionException pae) {    	
    // Handle
  }