#vulnerable code 
                                CloseableHttpResponse revalidateCacheEntry(
            final HttpRoute route,
            final HttpRequestWrapper request,
            final HttpClientContext context,
            final HttpExecutionAware execAware,
            final HttpCacheEntry cacheEntry) throws IOException, HttpException {

        final HttpRequestWrapper conditionalRequest = conditionalRequestBuilder.buildConditionalRequest(request, cacheEntry);
        final URI uri = conditionalRequest.getURI();
        if (uri != null) {
            try {
                request.setURI(URIUtils.rewriteURIForRoute(uri, route));
            } catch (final URISyntaxException ex) {
                throw new ProtocolException("Invalid URI: " + uri, ex);
            }
        }

        Date requestDate = getCurrentDate();
        CloseableHttpResponse backendResponse = backend.execute(
                route, conditionalRequest, context, execAware);
        Date responseDate = getCurrentDate();

        if (revalidationResponseIsTooOld(backendResponse, cacheEntry)) {
            backendResponse.close();
            final HttpRequestWrapper unconditional = conditionalRequestBuilder
                .buildUnconditionalRequest(request, cacheEntry);
            requestDate = getCurrentDate();
            backendResponse = backend.execute(route, unconditional, context, execAware);
            responseDate = getCurrentDate();
        }

        backendResponse.addHeader(HeaderConstants.VIA, generateViaHeader(backendResponse));

        final int statusCode = backendResponse.getStatusLine().getStatusCode();
        if (statusCode == HttpStatus.SC_NOT_MODIFIED || statusCode == HttpStatus.SC_OK) {
            recordCacheUpdate(context);
        }

        if (statusCode == HttpStatus.SC_NOT_MODIFIED) {
            final HttpCacheEntry updatedEntry = responseCache.updateCacheEntry(
                    context.getTargetHost(), request, cacheEntry,
                    backendResponse, requestDate, responseDate);
            if (suitabilityChecker.isConditional(request)
                    && suitabilityChecker.allConditionalsMatch(request, updatedEntry, new Date())) {
                return responseGenerator
                        .generateNotModifiedResponse(updatedEntry);
            }
            return responseGenerator.generateResponse(updatedEntry);
        }

        if (staleIfErrorAppliesTo(statusCode)
            && !staleResponseNotAllowed(request, cacheEntry, getCurrentDate())
            && validityPolicy.mayReturnStaleIfError(request, cacheEntry, responseDate)) {
            try {
                final CloseableHttpResponse cachedResponse = responseGenerator.generateResponse(cacheEntry);
                cachedResponse.addHeader(HeaderConstants.WARNING, "110 localhost \"Response is stale\"");
                return cachedResponse;
            } finally {
                backendResponse.close();
            }
        }
        return handleBackendResponse(conditionalRequest, context, requestDate, responseDate,
                backendResponse);
    } 
                            #location 12 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                CachingExec(
            final ClientExecChain backend,
            final HttpCache responseCache,
            final CacheValidityPolicy validityPolicy,
            final ResponseCachingPolicy responseCachingPolicy,
            final CachedHttpResponseGenerator responseGenerator,
            final CacheableRequestPolicy cacheableRequestPolicy,
            final CachedResponseSuitabilityChecker suitabilityChecker,
            final ConditionalRequestBuilder conditionalRequestBuilder,
            final ResponseProtocolCompliance responseCompliance,
            final RequestProtocolCompliance requestCompliance,
            final CacheConfig config,
            final AsynchronousValidator asynchRevalidator) {
        this.cacheConfig = config != null ? config : CacheConfig.DEFAULT;
        this.backend = backend;
        this.responseCache = responseCache;
        this.validityPolicy = validityPolicy;
        this.responseCachingPolicy = responseCachingPolicy;
        this.responseGenerator = responseGenerator;
        this.cacheableRequestPolicy = cacheableRequestPolicy;
        this.suitabilityChecker = suitabilityChecker;
        this.conditionalRequestBuilder = conditionalRequestBuilder;
        this.responseCompliance = responseCompliance;
        this.requestCompliance = requestCompliance;
        this.asynchRevalidator = asynchRevalidator;
    }