1: What is an abstract class and an abstract method? Explain using the below code. 

2: What is an interface? How are they different from abstract classes? Explain using the below code. 

3: Explain the difference between the three access types public, private and protected. Explain briefly using the below code. 

4: Write an example class that uses both the abstract class and the interface. Just the minimum skeleton of the required functions need to be shown. Body of the function need not be shown. Just the relevant details need to be shown.

3 4 2 public abstract class Room { protected double length; protected double width; protected double height; protected int numOfDoors = 1; protected int numOfWindows; 5 6 7 8 90 10 11 12 13 14 15 16 17 18 19 200 public Room( double 1, double w, double h, int now) { length = 1; width = w; height = h; numOfWindows = now; 29 30 } } /* gets and sets are not shown here */| abstract public double calcFloor Area(); abstract public double calcWallArea(); public String toString() { //Not completed. String retStr = ""; return retStr; 21 22 23 24 25 } 26 27 interface Plumbing{ 28 } public static final String agency = "Broward Water Agency"; public abstract boolean setWaterConnection();