Error 415 Unsupported Media Type: POST not reaching REST if JSON, but it does if XML

Add Content-Type: application/json and Accept: application/json in REST Client header section

The issue is in the deserialization of the bean Customer. Your programs knows how to do it in XML, with JAXB as Daniel is writing, but most likely doesn't know how to do it in JSON.

Here you have an example with Resteasy/Jackson http://www.mkyong.com/webservices/jax-rs/integrate-jackson-with-resteasy/

The same with Jersey: http://www.mkyong.com/webservices/jax-rs/json-example-with-jersey-jackson/

Just in case this is helpful to others, here's my anecdote:

I found this thread as a result of a problem I encountered while I was using Postman to send test data to my RESTEasy server, where- after a significant code change- I was getting nothing but 415 Unsupported Media Type errors.

Long story short, I tore everything out, eventually I tried to run the trivial file upload example I knew worked; it didn't. That's when I realized that the problem was with my Postman request. I normally don't send any special headers, but in a previous test I had added a "Content-Type": "application/json" header. OF COURSE, I was trying to upload "multipart/form-data." Removing it solved my issue.

Moral: Check your headers before you blow up your world. ;)