Student.java

class Person {   // removed 'public'
    String name;

    Person(String name){
       this.name = name;
    }
}

public class Student extends Person {
    int rollNo;
    String section;

    Student(String name, int rollNo, String section){
       super(name);
       this.rollNo = rollNo;
       this.section = section;
    }

    public void printDetails() {
       System.out.print("Student Details: ");
       System.out.println(this.name+ ", " + this.rollNo + ", " + section);
    }

    public static void main(String[] args) {
       Students student1 = new Students("Robert", 1, "IX Blue");
       Students student2 = new Students("Adam", 2, "IX Red");
       Students student3 = new Students("Julie", 3, "IX Blue");

       student1.printDetails();
       student2.printDetails();
       student3.printDetails();
    }
}