In order for the code bellow to work:

► Make sure to update the variables ("solrUrl", "collectionName", ...) with your information.

To force the commit, make sure to set the property "openSearcher" to true (SolrConfigXml file -> updateHandler -> autoCommit)

Note: You can also force the commit by running the URL: http://localhost:8983/solr/COLLECTION-NAME/update?commit=true

Delete documents using the request handler /update:

final String UPDATE_REQUEST_PATH = "/update";

final String[] solrUrl = { "http://localhost:8983/solr" };

final String collectionName = "collection1";

final CloudSolrClient cloudSolrClient = new CloudSolrClient.Builder(Arrays.asList(solrUrl)).build();

cloudSolrClient.setDefaultCollection(collectionName);

// deleting documents [/update] [UpdateRequest::deleteById]
{
    final UpdateRequest updateRequest = new UpdateRequest();

    updateRequest.deleteById("1");
    updateRequest.setPath(UPDATE_REQUEST_PATH);
    updateRequest.setMethod(METHOD.POST);

    final NamedList<Object> response = cloudSolrClient.request(updateRequest);

    System.out.println(response);
}

cloudSolrClient.close();