On an OEL7 system with Intel(R) Xeon(R) Platinum 8167M CPU @ 2.00GHz CPUs, this test code:

long start = System.currentTimeMillis();
HttpClient.Builder bldr = HttpClient.newBuilder();
HttpClient client = bldr.build();
long time = System.currentTimeMillis() - start;
System.out.printf("Client built in %d%n", time);

shows that the build() call takes over 300ms. This is a significant overhead if used in a command line tool where a single client is used.

Tested with JDK 17.0.2 and 11.0.14.