SolrJ - Can't commit updates when authentication plugin is enabled - solr

Question

With Solr 6.3.0, in cloud mode, and 3 external zookeepers as cluster, and use solrJ as client.
A: Without authentication
Before enabling authentication, I use following code to add/update document:
CloudSolrClient client = cloudClientBuilder.build();
UpdateResponse resp = client.add(doc, 5000);
client.commit();
client.close();
return resp;
It works well, the new document is in searching result immediately.
B: With authentication enabled
Then I enabled basic authentication plugin and rule-based authorization plugin (and SSL if that matters).
In order to set credential information, the code is refactored as following:
// create request,
UpdateRequest req = new UpdateRequest();
// add doc to request,
req.add(doc, 5000);
// set credential,
req.setBasicAuthCredentials(user, password);
// create client,
CloudSolrClient client = cloudClientBuilder.build();
client.setDefaultCollection(ConfigUtil.getProp(ConfigUtil.KEY_SOLR_CORE));
// do request & get response,
UpdateResponse resp = req.process(client);
client.commit();
client.close();
Then it will get error similar as this:
Error 401 require authentication, require authentication.
When debugging, the error occurs at line client.commit();.
Try with curl
I use curl to make an update:
curl -k --user solr:password "https://localhost:8983/solr/corexxx/update?wt=json&indent=true&commit=true" -d '[{"id":"20041", "name":"xxx 41", "location":"xxx", "description":"xxx"}]'
It committed successfully ! And, the updates are visible in searching result immediately.
My guess
Since curl works well, I guess solr cloud itself works fine.
Thus the issue is due to the code from B which is based on SolrJ.
Questions:
Why code B get HTTP 401 error? How can I fix it?
Could I use code from A, and still able to provide credential information,if yes, then how?
Thanks.

Answer 1

You should change client.commit() for req.commit(client, ConfigUtil.getProp(ConfigUtil.KEY_SOLR_CORE)), the credentials are setted in the UpdateRequest.

Answer 2

It worked like this:
SolrClient client = new HttpSolrClient.Builder(urlString).build();
UpdateRequest up = new UpdateRequest();
up.setBasicAuthCredentials(user, pass);
up.add(doc1);
up.process(client, core);
up.commit(client, core);
client.close();