java.lang.IllegalStateException: Connection pool shut down while using spring RestTemplate

Question

We are getting connection pool shutdown error while executing http requests using RestTemplate.

This is not a frequent error. It happened around 3 times in a month for a very short duration (less than a minute).

We are using PoolingHttpClientConnectionManager with 50 max connections and connectTimeout=60sec

  @Bean
  public RestTemplate restTemplate()
  {
    final RestTemplate restTemplate = new RestTemplate ( httpRequestFactory () );
    return restTemplate;
  }

  @Bean
  public ClientHttpRequestFactory httpRequestFactory()
  {
    return new HttpComponentsClientHttpRequestFactory ( httpClient () );
  }

  @Bean
  public CloseableHttpClient httpClient()
  {
    final SSLContext sslcontext = SSLContexts.createSystemDefault ();
    final X509HostnameVerifier hostnameVerifier = new BrowserCompatHostnameVerifier ();
    final Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder
      .<ConnectionSocketFactory> create ()
      .register ( "http", PlainConnectionSocketFactory.INSTANCE )
      .register ( "https", new SSLConnectionSocketFactory ( sslcontext, hostnameVerifier ) )
      .build ();

    final PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager (
      socketFactoryRegistry );
    connectionManager.setMaxTotal ( 50 );
    final RequestConfig config = RequestConfig.custom ()
      .setConnectTimeout ( 60000 ).build ();

    final CloseableHttpClient defaultHttpClient = HttpClientBuilder
      .create ().setConnectionManager ( connectionManager )
      .setDefaultRequestConfig ( config ).build ();

    LOGGER.info ( "Initializing CloseableHttpClient" );
    return defaultHttpClient;
  }

spring-webmvc version 4.0.6.RELEASE;
httpclient version 4.3.5

The exact stack trace is as follows...

java.lang.IllegalStateException: Connection pool shut down
        at org.apache.http.util.Asserts.check(Asserts.java:34) ~[httpcore-4.3.2.jar:4.3.2]
        at org.apache.http.pool.AbstractConnPool.lease(AbstractConnPool.java:169) ~[httpcore-4.3.2.jar:4.3.2]
        at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.requestConnection(PoolingHttpClientConnectionManager.java:221) ~[httpclient-4.3.5.jar:4.3.5]
        at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:158) ~[httpclient-4.3.5.jar:4.3.5]
        at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:195) ~[httpclient-4.3.5.jar:4.3.5]
        at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:86) ~[httpclient-4.3.5.jar:4.3.5]
        at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:108) ~[httpclient-4.3.5.jar:4.3.5]
        at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184) ~[httpclient-4.3.5.jar:4.3.5]
        at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82) ~[httpclient-4.3.5.jar:4.3.5]
        at org.springframework.http.client.HttpComponentsClientHttpRequest.executeInternal(HttpComponentsClientHttpRequest.java:87) ~[spring-web-4.0.6.RELEASE.jar:4.0.6.RELEASE]
        at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-4.0.6.RELEASE.jar:4.0.6.RELEASE]
        at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:52) ~[spring-web-4.0.6.RELEASE.jar:4.0.6.RELEASE]
        at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:545) ~[spring-web-4.0.6.RELEASE.jar:4.0.6.RELEASE]
        at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:506) ~[spring-web-4.0.6.RELEASE.jar:4.0.6.RELEASE]
        at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:243) ~[spring-web-4.0.6.RELEASE.jar:4.0.6.RELEASE]

Answer 1

try to change your code like this:

HttpClients.custom().setConnectionManager(manager).setConnectionManagerShared(true).build();

the setConnectionManagerShared will defines the connection manager is to be shared by multiple client instances.