Webservice applications ,either SOAP or REST send a lot of information in the headers along with the actual message.Most of the information is not captured in the application logs.
For debugging web service client/server applications , it is necessary to see the exact message that is sent on the wire i.e HTTP message along with the HTTP headers. Application logs usually print only the webservice request and printing the HTTP headers needs additional configuration based on the specific library being used.
SOAP UI- sample Raw HTTP message
Eclipse and IntelliJ provide plugins which help to intercept the HTTP messages sent between the client and server by acting as Man in the Middle.This is a very useful feature to debug the HTTP requests generated by application code and is very easy to setup.
Client/Server — Normal Communication
Client/Server — Communication with TCP Monitor
Eclipse Plugin — TCP/IP Monitor
TCP/IP Monitor -Eclipse
IntelliJ Plugin — TunneliJ
TunnelliJ HTTP Monitor
For advanced debugging and monitoring of TCP traffic, Wireshark can be used. I will try to cover this in a separate post.