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CXF also has an HTTP client transport that is based on the Apache HTTP Components HttpAsyncClient library. The HttpAsyncClient library uses a non-blocking IO model. This allows many more requests to be outstanding without consume consuming extra background threads. It also allows greater control over things like Keep-Alive handling which is very difficult or impossible with the HttpURLConnection based transport. However, the non-blocking model does not perform quite as well as the blocking model for pure synchronous request/response transactions.
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