-Interface IResearchScholar has two methods: public void teaches (string str) and public void studies (String str). - Define classes JuniorRS and SeniorRS such that JuniorRS implements IResearchScholar and SeniorRS extends JuniorRS. -Class InterAbstrTest extends SeniorRS, and has the main method. An object of JuniorRS invokes the method studies, and an object of SeniorRS invokes methods studies and teaches.

JAVA CODE Write a java set of classes that could be used to do simple calculations on geometricobjects. The set should include the following classes: a) Shapes ,containing abstract methods( a methods that is declared without animplementation) area and perimeter b) Rectangle, a subclass of Shape, containing a constructor (with parameters forlength and width) along with methods area and perimeter. c) Triangle, a subclass of Shape, containing a constructor (with parameters for the three sides of a triangle) along with methods area ( s = (a+b+c)/2, A = sqrt( s(s-a)(s-b)(s-c) ) ) and perimeter d) Square, a subclass of Rectangle, containing a constructor (with a parameter for thelength of a side) and methods that invoke the methods of the Rectangle class todetermine the perimeter and area of a square.

1. An abstract class called Pet is defined below: public abstract class Pet{ private String id;private String name; private static int count = 0; public Pet(String name)  {  count++; id = "P" + count; this.name = name; }  public String toString()  {  return "ID: " + id + ", Name: " + name; } abstract public void sound();} The Cat class is a subclass of the Pet class. The class specifications are given below:• It has a private field named age to record the cat’s age.• The class constructor sets both name and age fields of the cat with the given parameter values. The field age is set to 0 if the given value is negative. • It provides an accessor method for the field age. • It overwrites the toString method to return a string consisting of the cat’s ID, nameand age. e.g.ID: P15, Name: Molly, Age: 4• It prints out "Miaow" in a terminal when the method sound is called. Define the Cat class in full.

Given: interface B void methodA(); class C implements B { void methodB(){ } } everything is fine methodA should be overriden in class C O class C should be abstract O either b or c

1. Define a Class: Circle Circle - radius: double + Circle() +Circle(double r) +setradius(double r): void +getradius() : double +calculateArea(): double +calculateCircumference: double 2. Use a Circle instance (object) in a main() method Program.

Interfaces are used to define stronger is-a relationships because one class can inherit multiple interfaces.  Ture or false

In the class diagram below we have a parking charge class for an object-oriented parking system that is to be designed using java. Briefly explain any implementation decisions and the reasoning behind those without writing the complete code. N.B explain how the implementation will proceed instead of writing code

Given a Student class, and UndergradCourse is a true subtype of Course, there is one method called recommend in the Student class:  public class Student {     public Course recommend(Course pCourseID); } Please evaluate if EACH of the method in UndergradStudent class violates the Liskov Substitution Principle. public class UndergradStudent extends Student { 1. public Course recommend(UndergradCourse pCourseID); 2. public UndergradCourse recommend(Course pCourseID); 3. public UndergradCourse recommend(Object pCourseID); 4. public Course recommend(Course pCourseID) throw SomeCheckedException;

class A {protected int x1,y1,z; public: A(a, b,c):x1(a+2),y1(b-1),z(c+2) { for(i=0; i<5;i++) x1++;y1++;z++;}}; class B {protected: int x,y; public: B(a,b):x(a+1),y(b+2) { for(i=0; i<5;i++) x+=2; y+=1;}}; class D:public B, virtual public A { private: int a,b; public: D(k,m,n): a(k+n), B(k,m),b(n+2),A(k,m,n) { a=a+1;b=b+1;}}; int main() (Dob(4,2,5);} what the values of x1,y1 and z

Class student inherits from superclass Person. Which assignment is legal? a) Student s = new Person(); b) Person p = new Student(); c) Student s = new Student(); d) Person p = new Person();