objects. Support the following classes $($at least$)$: Countries States$/$Provinces Cities Boundaries RiversSupport the following operations, where applicable, plus any others that seem useful $($argumentshave been omitted, but you will have to include them$)$: area$()$ capital$()$ getCities$()$ getCountry$()$ distance$()$ between cities boundaryLength$()$ total length of boundary neighbors$()$ objects sharing boundaries borderOf$()$ the countries$/$states this boundary segment separatesWrite out the class definitions, instance variables and method definitions. Some of the instancevariables should probably be various kinds of Collections. You do not need to implement themethods, but you should include comments inside each method that describe the approach you wouldtake $($alternately$,$ you can actually implement them that might be simpler for some methods$).$ Useinterfaces and superclasses where appropriate. Supply javadoc comments for all classes, interfaces,and methods. The system you write should compile, even if it doesnt actually work $($because themethods are just stubs with comments$).$ Identify all of the classes as belonging to the packag