#vulnerable code 
                                protected boolean isFiltered(LogEvent event) {
        if (hasFilters) {
            for (Filter filter : filters) {
                if (filter.filter(event) == Filter.Result.DENY) {
                    return true;
                }
            }
        }
        return false;
    } 
                            #location 2 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                protected boolean isFiltered(LogEvent event) {
        Filters f = filters;
        if (f.hasFilters()) {
            for (Filter filter : f) {
                if (filter.filter(event) == Filter.Result.DENY) {
                    return true;
                }
            }
        }
        return false;
    }