Use the initialize() method. Create a list of SpecificEntity. For every member of the IMendixObject list use
SpecificEntity specificEntity = SpecificEntity initialize(getContext(), IMendixObjectList.get(i));
The method initialize is deprecated. You could use the method load with the same parameters mentioned by Chris nowadays.
I think classname.initialize() or classname.load() have the same result, an object with getters and setters?! I didn't know that class.load had been depreciated. Thanks Evandro. I think classname.initialize() is still being used in the autogenerated code of my java actions in version 6.10.10. But I will use classname.load() from now on!