org.apache.jmeter.control
Interfaces 
Controller
ReplaceableController
Classes 
CriticalSectionController
ForeachController
GenericController
IfController
IncludeController
InterleaveControl
LoopController
ModuleController
OnceOnlyController
RandomController
RandomOrderController
RunTime
SwitchController
TestFragmentController
ThroughputController
TransactionController
TransactionSampler
WhileController
Exceptions 
NextIsNullException