The ClientLoader.load method in the Loader interface provides a client load function that satisfies most scenarios. However, if you want to load data without the ClientLoader.load method, you can implement your own preload utility.
// Get the StateManager
StateManager stateMgr = StateManagerFactory.getStateManager();
// Set ObjectGrid state to PRELOAD before calling ClientLoader.loader
stateMgr.setObjectGridState(AvailabilityState.PRELOAD, objectGrid);
// Load the data
...<your preload utility implementation>...
// Set ObjectGrid state back to ONLINE
stateMgr.setObjectGridState(AvailabilityState.ONLINE, objectGrid);