It is recommended to have an appropriate header parameter in the client request and in the server response to indicate how the entity body is serialized when transmitted over a wire:

• Accept: This request header field defines a list of acceptable response formats for the response, for example, Accept: application/json,application/xml.

The javax.ws.rs.client.WebTarget class allows you to specify the Accept header via the request() method for a JAX-RS client application.

• Content-Type: This header field defines the type of the request or response message body content, for example, Content-Type: text/plain; charset=UTF-8.