According to the explanation for example 07-1 in Bill Burke's RESTful Java with JAX-RS book (page 238): "One thing to notice about this client code is that if the server returns a 404 response code, HttpURLConnection will throw a java.io.FileNotFoundException." The book may be wrong, because the server is returning a 404 but no FNFE is being thrown. (I've tested it by putting a debugging statement in CustomerResourceTest.testCustomerResource()). If the book is in error, this example should be rewritten to return the "Customer not found" string even though the FNFE is not being thrown. Or, fix the code so the FNFE will be thrown so the user will see this message.