What role do packages have in the development of classes? Identify valid and invalid import statements amongst the following list: import java.*; import javafx.scene.*; import java.util.Scanner;...

What role do packages have in the development of classes? Identify valid and invalid import statements amongst the following list: import java.*; import javafx.scene.*; import java.util.Scanner; import javax.scene.control.Button; import java.application.Application; import java.text.*.*;