what' referencewe'll discuss references in more detail later in the meantimethink of it as name for an object (it' actually the object' addressbut you don' need to know that here' how we would create two references to type thermostatcreate two new thermostat objectsand store references to them in these variablesthermostat therm therm /create two references therm new thermostat()/create two objects and therm new thermostat()/store references to them incidentallycreating an object is also called instantiating itand an object is often referred to as an instance of class accessing object methods once you've specified class and created some objects of that classother parts of your program need to interact with these objects how do they do thattypicallyother parts of the program interact with an object' methods (functions)not with its data (fieldsfor exampleto tell the therm object to turn on the furnacewe would say therm furnace_on()the dot operator associates an object with one of its methods (or occasionally with one of its fieldsat this point we've covered (rather telegraphicallyseveral of the most important features of oop to summarizeobjects contain both methods (functionsand fields (dataa class is specification for any number of objects to create an objectyou use the keyword new in conjunction with the class name to invoke method for particular object you use the dot operator these concepts are deep and far-reaching it' almost impossible to assimilate them the first time you see themso don' worry if you feel bit confused as you see more classes and what they dothe mist should start to clear runnable object-oriented program let' look at an object-oriented program that runs and generates actual output it features class called bankaccount that models checking account at bank the program creates an account with an opening balancedisplays the balancemakes deposit and withdrawaland then displays the new balance here' the listing for bank java/bank java