Apache PoolingHttpClientConnectionManager throwing illegal state exception

Question

Here is how I use it -

private static final PoolingHttpClientConnectionManager connPool;  static {          connPool = new PoolingHttpClientConnectionManager();         // Increase max total connection to 200         connPool.setMaxTotal(200);//configurable through app.properties         // Increase default max connection per route to 50         connPool.setDefaultMaxPerRoute(20);//configurable through app.properties  }  CloseableHttpClient httpClient = HttpClients.custom()                 .setConnectionManager(connPool) .build(); 

ALso I have put a finally block around http GET -

finally {             try {                 httpClient.close();             } catch (IOException e) {                 LOGGER.error(e.getMessage());                }         } 

Here is my stacktrace -

java.lang.IllegalStateException: Connection pool shut down     at org.apache.http.util.Asserts.check(Asserts.java:34)     at org.apache.http.pool.AbstractConnPool.lease(AbstractConnPool.java:169)     at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.requestConnection(PoolingHttpClientConnectionManager.java:217)     at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:157)     at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:194)     at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:85)     at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:108)     at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:186)     at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)     at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:106)     at com.A.B.C.CustomHttpClient.doGETAndValidate(CustomHttpClient.java:44)     at com.A.B.C.SiteMonitorTask.monitorAndUpdateEndPoints(SiteMonitorTask.java:48)     at com.A.B.C.SiteMonitorTask.run(SiteMonitorTask.java:37)     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)     at java.lang.Thread.run(Thread.java:744) 

I am using Quartz to schedule a job of monitoring Http end points.. Here is my connection pool configuration

totalMaxHttpConn=200 maxHttpConnPerRoute=20 

Maven dependency.. artifact version

httpclient 4.3.1 httpcore 4.3.1 

EDIT - Well the problem got away by not closing CloseableHttpClient in the finally block.. Can anyone tell why is it behaving like that? Why is connection pool shut down if i close a client?

Is the closeablehttpclient above is a handle to the pool rather than a single conn

Answer 1

In version 4.4 the method setConnectionManagerShared(boolean) was added to HttpClientBuilder.

If you set it to true the client won't close the connection manager.

HttpClients.custom()             .setConnectionManager(Util.getConnectionManager()) // shared connection manager             .setConnectionManagerShared(true) 

Answer 2

This behavior is due to a bug in HC 4.3. It has already been fixed in HC 4.4a1. As of 4.4 CloseableHttpClient#close should automatically shut down the connection pool only if exclusively owned by the client