All phones must have a way of making and then terminating a connection to the phone network; however the exactprocedure for doing so depends upon the nature of the phone (e. g. landline, cell phone, satellite phone).write a abstract class, phone, that contains a string instance variable, phonenumber, a constructor thataccepts a string parameter initializing the instance variable, an accessor method, getphonenumber, that returns the phonenumber, a tostring method that return the phonenumber in the form #(phonenumber), and two abstract methods: a boolean-valued method named createconnection that returns a boolean and accepts an reference to an object oftype network, and a void-returning method, closeconnection, that accepts no parameters