Question

I have a loop over a bunch of URLs, for each one I’m doing the following:

private String doQuery(String url) {

  HttpGet httpGet = new HttpGet(url);
  setDefaultHeaders(httpGet); // static method
  HttpResponse response = httpClient.execute(httpGet);   // httpClient instantiated in constructor

  int rc = response.getStatusLine().getStatusCode();

  if (rc != 200) {
    // some stuff...
    return;
  }

  HttpEntity entity = response.getEntity();

  if (entity == null) {
    // some stuff...
    return;
  }

  // process the entity, get input stream etc

}

The first query is fine, the second throws this exception:

Exception in thread “main”
java.lang.IllegalStateException:
Invalid use of
SingleClientConnManager: connection
still allocated. Make sure to release
the connection before allocating
another one. at
org.apache.http.impl.conn.SingleClientConnManager.getConnection(SingleClientConnManager.java:199)
at
org.apache.http.impl.conn.SingleClientConnManager$1.getConnection(SingleClientConnManager.java:173)……

This is just a simple single-threaded app. How can I release this connection?

Answer 1

To answer my own question: to release the connection (and any other resources associated with the request) you must close the InputStream returned by the HttpEntity:

InputStream is = entity.getContent();

.... process the input stream ....

is.close();       // releases all resources

From the docs