Data types in Java for ICSE Class 10, with casting and Scanner input.

import java.util.Scanner;

public class Pitfall2 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Flat number: ");
        int flat = in.nextInt();
        System.out.print("Society: ");
        String society = in.nextLine();
        System.out.println(flat + ", " + society + ".");
    }
}
// Typed: 402, Enter, Green Meadows, Enter
// Printed: 402, .

The program printed the second prompt and finished at once: society is the empty String left over from the first line.

import java.util.Scanner;

public class Fixed2 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Flat number: ");
        int flat = in.nextInt();
        in.nextLine();
        System.out.print("Society: ");
        String society = in.nextLine();
        System.out.println(flat + ", " + society + ".");
    }
}
// Typed: 402, Enter, Green Meadows, Enter
// Printed: 402, Green Meadows.

The lone in.nextLine() reads and throws away the line end after 402, so the next call waits for the society name.

import java.util.Scanner;

public class Report {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Name: ");
        String name = sc.nextLine();
        System.out.print("Marks in 5 subjects: ");
        int total = 0;
        for (int k = 1; k <= 5; k++)
            total += sc.nextInt();
        double percent = total / 5.0;
        int rounded = (int) Math.round(percent);
        char band = percent >= 90 ? 'A' : percent >= 75 ? 'B' : 'C';
        System.out.println(name + ": total " + total + ", "
            + percent + "%, rounded " + rounded + ", band " + band);
    }
}
// Input: Ishaan Mehta / 88 92 79 95 82
// Ishaan Mehta: total 436, 87.2%, rounded 87, band B

Reading the full name before any number sidesteps the pitfall entirely. Two casts appear: 5.0 makes the percentage a double, and (int) turns the long from Math.round into an int.