Welcome back, Sujit Kumar Mishra

What is circular dependency? 

Circular dependency happens when two or more things depend on each other directly or indirectly, creating a loop that can cause problems.

Example:

Imagine there are two files in a program:

1: File A needs something from File B

2: File B also needs something from File A

Because both files are waiting for each other, it creates a circle, and the program might not work properly.

In short:

Circular dependency is like two friends who each refuse to start a task until the other does, so nothing ever gets done.

Real-Time Example: Student and Course

Suppose you are designing a school system where:

1: Each Student is enrolled in a Course.

2: Each Course keeps track of the Student as a representative.

If both classes directly reference each other in their fields, you create a circular dependency.

Student.java

public class Student {
    private String name;
    private Course course; 
             // Student is enrolled in a Course

    public Student(String name, Course course) {
        this.name = name;
        this.course = course;
    }
}

Course.java

public class Course {
    private String title;
    private Student representative; 
              // Course has a Student as representative

    public Course(String title, Student representative) {
        this.title = title;
        this.representative = representative;
    }
}

What happens?

1: When you try to create a Student, you need a Course.

2: When you try to create a Course, you need a Student.

3: This can make it difficult to initialize objects without running into issues, because each one requires the other to exist first.

How to avoid this?

1: Use setter methods to assign one property after initial creation.

2: Use interfaces or design patterns to decouple the classes.