You should read those tutorials:
Basically you should select value container for selectOneMenu tag. it means that it should look like:
<h:selectOneMenu value="#{comyon.selectedItem}">
<f:selectItems id="meslek7" value="#{comyon.selectıtem}"/>
</h:selectOneMenu>
and if you need to pass a object not string you should use converter. Look at the links on the top.