Websphere problems when setting up Http Connection Pool for RestTemplate

Question

I'm working with Spring 4.0.3.RELEASE version. I'm able to make restful calls successfully. However, I learnt that HTTP connections are expensive and thought of using connection pool. I read few articles like this and this. Everything is fine when I include the dependency with Maven3 and compile. The problems arise during runtime. With this code, I get class not found exception for PoolingHttpClientConnectionManager.

public RestTemplate restTemplate(){
    HttpHost host = new HttpHost("localhost", 9081);
    PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
    // Increase max total connection to 200
    cm.setMaxTotal(200);
    cm.setDefaultMaxPerRoute(50);       
    cm.setMaxPerRoute(new HttpRoute(host), 20);

    HttpClientBuilder httpClientBuilder = HttpClientBuilder.create().setConnectionManager(cm);
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(
            httpClientBuilder.build());
    return new RestTemplate(requestFactory);
}

And with this code, I get class not found exception for HttpClients.

public RestTemplate restTemplate(){
        RestTemplate restTemplate = new RestTemplate();
        HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
        requestFactory.setConnectTimeout(20000);
        requestFactory.setReadTimeout(20000);       
        restTemplate.setRequestFactory(requestFactory); 
        return  restTemplate;
    }

I'm deploying on Websphere 8.5. And I tried different versions of httpclient from 4.0.1 to 4.5.2 with different scope (provided, compile) with no luck. Thanks in advance for any hint in the right direction.

score 1 · Accepted Answer · answered May 16 '16 at 19:43

So, it's basically a problem with Websphere 8+ versions including httpclient with their jvm library. Luckily, our Enterprise Websphere are all 7.5.x version. So, if we bundle the httpclient with the ear, it does not cause any issue in production or pre-production.

For those, who have to use Websphere 8.x versions, please use the shared isolated library approach as defined here. I used that for my local 8.5 Websphere and it works pretty neat.

score 0 · Answer 2 · answered Jun 18 '17 at 20:21

0

you should stop the application and then go to manage module tab in websphere and and on "Class loader order" combo box choose "parent last" item and then start application. problem solved...

answered Jun 18 '17 at 20:21

siawash

1
1

This is not the right way. As mentioned in the marked answer, shared library approach is the right way to refer to a jar, which is different from the Websphere container library. – Kabira Speaking Jun 26 '17 at 18:48

Websphere problems when setting up Http Connection Pool for RestTemplate

2 Answers2