Level 6 — Programming — Jul/Aug 2025 — Written

Question 1

Answer

final String NAME = "Mary";
final int AGE = 25;

Question 2

Answer

• Compiler: javac translates source into JVM bytecode.
• Interpreter: the JVM can interpret bytecode instructions.
• Just-in-time (JIT) compiler: converts frequently executed bytecode to native machine code. An assembler is a general translator category but is not normally part of a Java programmer’s source-to-bytecode workflow.

Question 3

Answer

• Begin with a valid Java identifier-start character, such as a letter or underscore; do not begin with a digit.
• Use valid identifier characters thereafter; no spaces or punctuation such as a hyphen.
• Do not use a keyword or reserved literal as an identifier. A lone underscore is reserved in modern Java.
• Java identifiers are case-sensitive; use a consistent readable convention such as camelCase.

Question 4

Answer

• Use System.out.println(“Area”); — System begins with uppercase S and out is lowercase.
• The application entry method is public static void main(String[] args), with lowercase main.
• Backslash is not Java’s division operator, and an expression such as x/2 cannot be assigned a value. If the intended variable name was x2, a valid declaration is int x2 = 5;.
• while is a keyword; use a valid identifier such as int count;.

Question 5

Answer

Save as GradeChoice.java.

import java.util.Scanner;
public class GradeChoice {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter 1, 2 or 3: ");
        int number = in.nextInt();
        switch (number) {
            case 1: System.out.println("Distinction"); break;
            case 2: System.out.println("Credit"); break;
            case 3: System.out.println("Pass"); break;
            default: System.out.println("Invalid selection");
        }
    }
}

Question 6

Answer

// Single-line explanation
/* A comment
   across several lines. */

Question 7

Answer

The fourth expression is a == b in the original scan; the OCR text dropped part of it.

Question 8

Answer

public class vehicle {
    public void parts() {
        System.out.println("Engine, wheels and brakes");
    }
}
// From another method:
// vehicle v = new vehicle();
// v.parts();

Question 9

Answer

if (average >= 80 && average <= 100) {
    System.out.println("Excellent");
} else if (average >= 60 && average < 80) {
    System.out.println("Good");
}

For fractional averages, the lower category uses [60,80); for integer marks this is exactly 60–79. Validate the overall 0–100 range before classifying.

Question 10

Answer

int[] marks = {45, 56, 67, 100};
for (int mark : marks) {
    System.out.println(mark);
}

Question 11

Answer

Save as DayDemo.java.

public class DayDemo {
    enum day { Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday }
    public static void main(String[] args) {
        for (day d : day.values()) System.out.println(d);
    }
}

Question 12

Answer

• Source code: human-readable program text.
• Object code: translated output, often intermediate/native code requiring a runtime or linking. For Java, .class files contain JVM bytecode.
• Machine code: binary instructions for a specific CPU architecture.

String word = "  Java  ";
System.out.println(word.length());        // 8
System.out.println(word.trim());          // Java
System.out.println(word.substring(2, 6)); // Java
System.out.println(word.toUpperCase());  // two spaces + JAVA + two spaces

The Java method name is toUpperCase(), correcting the paper’s “toppercase” spelling.

Save as Calculate.java.

class goods {
    protected double price;
    protected int quantity;
    goods(double price, int quantity) {
        this.price = price; this.quantity = quantity;
    }
}
public class Calculate extends goods {
    Calculate(double price, int quantity) { super(price, quantity); }
    double getCost() { return price * quantity; }
    public static void main(String[] args) {
        Calculate item = new Calculate(100, 10);
        System.out.printf("Cost = KSh %.2f%n", item.getCost());
    }
}

Question 13

Answer

switch (Character.toUpperCase(color)) {
    case 'R': System.out.println("Red"); break;
    case 'B': System.out.println("Blue"); break;
    case 'G': System.out.println("Green"); break;
    default: System.out.println("Unknown colour");
}

Save as SquareRoots.java.

public class SquareRoots {
    public static void main(String[] args) {
        System.out.println("Number\tSquare root");
        for (int i = 1; i <= 10; i++) {
            System.out.printf("%d\t%.6f%n", i, Math.sqrt(i));
        }
    }
}

• Unary uses one operand: ++x, -x or !ready.
• Binary uses two operands: x+y, a<b or left&&right.

Question 14

Answer

The design is pseudocode: a language-independent textual algorithm.

Save as AddDesign.java.

public class AddDesign {
    public static void main(String[] args) {
        int a = 45, b = 55;
        int c = a + b;
        System.out.println(c);
    }
}

Output: 100. The original paper’s starting principal is KSh 1000; OCR incorrectly read 1600.

Save as CompoundInterest.java.

public class CompoundInterest {
    public static void main(String[] args) {
        double principal = 1000, rate = 10;
        int year = 1;
        System.out.println("Year\tPrincipal\tInterest\tAmount");
        do {
            double interest = principal * rate / 100;
            double amount = principal + interest;
            System.out.printf("%d\t%.2f\t\t%.2f\t\t%.2f%n",
                              year, principal, interest, amount);
            principal = amount;
            year++;
        } while (year <= 4);
    }
}

class Learner { String name; }
// Class: Learner is a template.
// Inside a method:
Learner mary = new Learner(); // mary refers to a created object

Question 15

Answer

class payroll {
    String name;
    double salary;
    payroll(String name, double salary) {
        this.name = name;
        this.salary = salary;
    }
}
// Inside a method:
payroll employee = new payroll("Johnson", 25000);

static int add(int a, int b, int c) { return a + b + c; }
static double add(double a, double b) { return a + b; }
static int add(int a, int b) { return a + b; }

Save as OddEven.java.

import java.util.Scanner;
public class OddEven {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Integer: ");
        int number = in.nextInt();
        System.out.println(number % 2 == 0 ? "Even" : "Odd");
    }
}