Please answer the question in Java. Pay attention to (a student is allowed to change name) in Question3 and ('A' becomes 'B', 'B' becomes 'C', 'C' becomes 'D', 'D' becomes 'F', 'F' stays an 'F', and any other grade becomes 'F' too) in question 6 Thanks.

This question is about the java program and it conclude six step.Please show every step's code in two class and answer the question :What is the problem if you make the ID instance variable public? " in Question 1. Thank you!

Step1:

Create a class Student that contains the following things: a private integer ID number; a constructor that takes as argument an ID number and uses this ID number to initialize the object's ID number; a public method getID that takes zero argument and returns the ID number of the student; a public static method testStudent that contains tests for your class. Here is the corresponding UML diagram (remember that + means public and - means private): +--------------------------+ | Student | +--------------------------+ | - ID: int | +--------------------------+ | + Student(int ID) | | + getID(): int | | + testStudent(): void | +--------------------------+ The Student class does not have a setID method because the ID number of a student never changes. How many tests should the testStudent method contain? Once you have written the Student class, you can test it by adding the following code in a new class called Start in the same project: public class Start { public static void main(String[] args) { Student.testStudent(); } } This code calls the static testStudent method of the Student class, which should then run all your tests. What is the problem if you make the ID instance variable public?

Step 2

Modify the constructor of the Student class so that negative ID numbers are not allowed when creating a Student object. If the constructor is given a negative ID number as argument then the constructor should use 0 for the ID number. Modify your testStudent method to test the new code. How many tests should the testStudent method now contain?

Step 3

Add to your Student class a string representing the name of the student. The constructor for the class should now take the name of the student as an extra argument. Also add to your class two methods getName and setName to get and change the name of a student (a student is allowed to change name). Here is the corresponding UML diagram: +--------------------------------+ | Student | +--------------------------------+ | - ID: int | | - name: String | +--------------------------------+ | + Student(int ID, String name) | | + getID(): int | | + getName(): String | | + setName(String name): void | | + testStudent(): void | +--------------------------------+ Note: we have not talked much about the String type in class yet. For now just use it like you use any other type (like int or float). Do not forget to modify your testStudent method to test the new code. In Java you can use == to compare constant strings.

Step 4

Add to your Student class a character representing the grade of the student. The default grade when a student is created is 'A'. Also add to your class two methods getGrade and setGrade to get and change the grade of a student. Here is the corresponding UML diagram: +--------------------------------+ | Student | +--------------------------------+ | - ID: int | | - name: String | | - grade: char | +--------------------------------+ | + Student(int ID, String name) | | + getID(): int | | + getName(): String | | + setName(String name): void | | + getGrade(): char | | + setGrade(char grade): void | | + testStudent(): void | +--------------------------------+ Do not forget to modify your testStudent method to test the new code. In Java you can use == to compare characters.

Step5

Add a new constructor to your Student class that takes three arguments as input: an ID number, a name, and an initial grade. Using this second constructor it becomes possible to create Student objects with an initial grade which is different from 'A'. Here is the corresponding UML diagram: +--------------------------------------------+ | Student | +--------------------------------------------+ | - ID: int | | - name: String | | - grade: char | +--------------------------------------------+ | + Student(int ID, String name) | | + Student(int ID, String name, char grade) | | + getID(): int | | + getName(): String | | + setName(String name): void | | + getGrade(): char | | + setGrade(char grade): void | | + testStudent(): void | +--------------------------------------------+ Do not forget to modify your testStudent method to test the new code.

Step 6

Add to your Student class a boolean indicating whether the student is currently sleeping in the lab or not. When a student is created, the student is awake. Also add to your class three methods: one method isSleeping that returns a boolean indicating whether the student is currently sleeping or not. one method goToSleep that makes the student fall asleep. When a student falls asleep, the grade of the student decreases by one letter grade ('A' becomes 'B', 'B' becomes 'C', 'C' becomes 'D', 'D' becomes 'F', 'F' stays an 'F', and any other grade becomes 'F' too). one method wakeUp that makes the student wake up. The grade of a student does not go up when the student wakes up. Here is the corresponding UML diagram: +--------------------------------------------+ | Student | +--------------------------------------------+ | - ID: int | | - name: String | | - grade: char | | - sleeping: boolean | +--------------------------------------------+ | + Student(int ID, String name) | | + Student(int ID, String name, char grade) | | + getID(): int | | + getName(): String | | + setName(String name): void | | + getGrade(): char | | + setGrade(char grade): void | | + isSleeping(): boolean | | + goToSleep(): void | | + wakeUp(): void | | + testStudent(): void | +--------------------------------------------+ public class Start { public static void main(String[] args) { Student.testStudent(); } }