<p>Can I access spring bean that exposed using http invoker (server) from GWT application (client)?</p>
<p>If so is there any example / tutorial for that?</p>

There's an application template for Spring-GWT apps available
here
, that you may find useful. I haven't tried it out, but I believe it's implemented as a Maven archetype.
For more background on exactly what this template does for you, and how to integrate GWT with Spring, check out the following (video)
presentation
.