#fixed code
                                @SuppressWarnings({"unchecked"})
    public boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws IOException {

        Subject subject = getSubject(request, response);
        String[] rolesArray = (String[]) mappedValue;

        if (rolesArray == null || rolesArray.length == 0) {
            //no roles specified, so nothing to check - allow access.
            return true;
        }

        Set<String> roles = CollectionUtils.asSet(rolesArray);
        return subject.hasAllRoles(roles);
    }
#vulnerable code 
                                @SuppressWarnings({"unchecked"})
    public boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws IOException {

        Subject subject = getSubject(request, response);
        Set<String> roles = (Set<String>) mappedValue;

        boolean hasRoles = true;
        if (roles != null && !roles.isEmpty()) {
            if (roles.size() == 1) {
                if (!subject.hasRole(roles.iterator().next())) {
                    hasRoles = false;
                }
            } else {
                if (!subject.hasAllRoles(roles)) {
                    hasRoles = false;
                }
            }
        }

        return hasRoles;
    } 
                            #location 14 
                            #vulnerability type NULL_DEREFERENCE