Welcome back, Sujit Kumar Mishra

Can you explain what is immutable class? 

An immutable class is a class whose objects cannot be changed after they are created.

Key Points:

1: Once you create an object of an immutable class, you cannot modify its values.

2: All fields (variables) in the class are usually marked as final and private.

3: There are no setter methods—only getter methods to access the values.

Example:

final class Student {
    private final String name;
    private final int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

Here, once a Student object is created, you cannot change its name or age.

In simple words:

Immutable means "unchangeable." Just like your birth date, once set, it cannot be changed!