The java.net.http.HttpClient is very heavy and hungry for resources (heap and threads primarily). Apache CXF tries to countermeasure that by sharing a single  java.net.http.HttpClient instance across many HTTP client conduits if possible (subject to HTTP client policy and SSL/TLS settings). This behaviour could be changed by setting share.httpclient.http.conduit contextual property to false (the default value is true), in this case a new java.net.http.HttpClient instance is going to be created per HTTP client conduit.