Q1) Find the issues in the following Java code, then correct them. public class

Q1) Find the issues in the following Java code, then correct them.
public class Rectangular
{
private int length;
private int width;
public Rectangular(int length, int width)
{
this.length = length;
this.width = width;
}
public String area ()
{
return length * width;
}
}
public class RectangularTest
{
public static void main (String[] args)
{
Rectangular r1 = new Rectangular(3,5);
System.out.println(area());
}
} Q2)
Create a Java class for Student with the following requirements:
Create a tester class with the main method with the following requirements.
Each student has two attributes: Name and ID.
Create two constructors. One constructor without parameters to initialize all the instance variables to default values, and another constructor to initialize all the attributes to specific values.
Add all setter and getter methods.
Create two objects from Student class. Create the first object using the default constructor and the second object must set your name and ID.
Print your name and ID using getter methods.
Q3)Suppose you have the following 2 dimensions array: int arr[][] = { { 10, 11, 12, 13, 14 }, { 15, 16, 17, 18, 19 }, { 20, 21, 22, 23, 24 }, { 25, 26, 27, 28, 29 }, { 30, 31, 32, 33, 34 } }; With the the following rows and columns sizes: static int rows= 5; static int columns= 5; Write a Java programs that uses takes arr[][] and reverse (mirror) all rows. For example, the first row should be as the following after you reverse it 14 13 12 11 10. A screenshot of your output should also be included in your answer and should display both the original array and the reversed array. Sample output:
Q4) What is the output of the following Java program? public class Exam { static int studyingHours = 31; private String course = “OOP”; public void compute(int studyingHours) { Exam e = new Exam(); this.studyingHours = 24; course = “Math”; System.out.println(“Exam.studyingHours: ” + Exam.studyingHours); System.out.println(“e.studyingHours: ” + e.studyingHours); System.out.println(“e.course: ” + e.course); System.out.println(“course: ” + course); } public static void main(String args[]) { Exam e = new Exam(); e.compute(31); } }