Jersey: com.sun.jersey.server.impl.template.ViewableMessageBodyWriter

I'm totally alien to Jersey. I'm trying to run a jar which throws javax.ws.rs.WebApplicationException when I hit the endpoint. The error thrown by the program is as follows:

09-Apr-2011 08:32:20 com.sun.jersey.spi.container.ContainerResponse write

SEVERE: A message body writer for Java class java.lang.String, and Java type class java.lang.String, and MIME media type application/json was not found

09-Apr-2011 08:32:20 com.sun.jersey.spi.container.ContainerResponse write

SEVERE: The registered message body writers compatible with the MIME media type are: / -> com.sun.jersey.server.impl.template.ViewableMessageBodyWriter

09-Apr-2011 08:32:20 com.sun.jersey.spi.container.ContainerResponse logExcept开发者_如何学JAVAion

Any ideas for where to start looking at for debugging?

Update: I've got javax.ws.rs.ext.MessageBodyWriter in the META-INF/services of the jar with the following content: com.sun.jersey.server.impl.template.ViewableMessageBodyWriter

And at the beginning of the program I see: com.sun.jersey.server.impl.application.WebApplicationImpl _initiate

---

You need to include jersey-json module on your class path - see the Jersey dependencies page, which has a list of dependencies you need to include based on the type of functionality you need: http://jersey.java.net/nonav/documentation/latest/chapter_deps.html