Type Alias BasicAppBuilder 

pub type BasicAppBuilder<ExecC, QueryC> = AppBuilder<BankKeeper, MockApi, MockStorage, FailingModule<ExecC, QueryC, Empty>, WasmKeeper<ExecC, QueryC>, StakeKeeper, DistributionKeeper, FailingModule<IbcMsg, IbcQuery, Empty>, FailingModule<GovMsg, Empty, Empty>, StargateKeeper<ExecC, QueryC>>;

This is essential to create a custom app with custom handler. let mut app = BasicAppBuilder::<E, Q>::new_custom().with_custom(handler).build();

Aliased Type

pub struct BasicAppBuilder<ExecC, QueryC> { /* private fields */ }