JDeveloper Group By Insight Preference
During Oracle OpenWorld a customer asked how to turn off the autogenerate of GROUP BY clause when using JDeveloper.

SQL Developer has a preference
But JDeveloper is missing this preference, and it is turned on by default.
This will be rectified in a future realese of JDeveloper but in the mean time there is a workaround.
1) Close JDeveloper.
2) Open JDevelopers product-preferences.xml file.
This can be found under
c:\Users\\AppData\Roaming\JDeveloper\\o.jdeveloper\
on windows 7. Or in the usual place applications persist preferences in your OS.
3)Add the following after the ide tag.
<hash n="DBConfig">
<value n="AUTOGENERATEGROUPBY" v="false"/>
<hash n="EXTENSION"/>
<value n="INDENT_CACHE_NUMBER" v="2"/>
<value n="INDENT_CACHE_USE_TAB" v="false"/>
</hash>
.
4) Restart JDeveloper, and Autogenerate GROUP BY should not turned off.