Return values in Java - Practice Problems & Coding Challenges

trophy

Challenge - 5 Problems

💻 code output

intermediate

What is the output of this Java method call?

Consider the following Java method:

public static int multiplyByTwo(int x) {
    return x * 2;
}

public static void main(String[] args) {
    System.out.println(multiplyByTwo(5));
}

What will be printed when main runs?

Java

public static int multiplyByTwo(int x) {
    return x * 2;
}

public static void main(String[] args) {
    System.out.println(multiplyByTwo(5));
}

A 25

B 5

C Compilation error

D 10

💻 code output

intermediate

What does this method return?

Look at this Java method:

public static String greet(String name) {
    if (name == null) {
        return "Hello, Guest!";
    }
    return "Hello, " + name + "!";
}

public static void main(String[] args) {
    System.out.println(greet(null));
}

What will be printed when main runs?

Java

public static String greet(String name) {
    if (name == null) {
        return "Hello, Guest!";
    }
    return "Hello, " + name + "!";
}

public static void main(String[] args) {
    System.out.println(greet(null));
}

A Hello, null!

B Hello, Guest!

C Hello, !

D NullPointerException

💻 code output

advanced

What is the output of this recursive method?

Consider this Java method:

public static int factorial(int n) {
    if (n <= 1) {
        return 1;
    }
    return n * factorial(n - 1);
}

public static void main(String[] args) {
    System.out.println(factorial(4));
}

What will be printed when main runs?

Java

public static int factorial(int n) {
    if (n <= 1) {
        return 1;
    }
    return n * factorial(n - 1);
}

public static void main(String[] args) {
    System.out.println(factorial(4));
}

A 10

B 1

C 24

D StackOverflowError

💻 code output

advanced

What is the value of x after this method call?

Given this Java code:

public static int addFive(int num) {
    num = num + 5;
    return num;
}

public static void main(String[] args) {
    int x = 10;
    addFive(x);
    System.out.println(x);
}

What will be printed when main runs?

Java

public static int addFive(int num) {
    num = num + 5;
    return num;
}

public static void main(String[] args) {
    int x = 10;
    addFive(x);
    System.out.println(x);
}

A 10

B 15

C 5

D Compilation error

🧠 conceptual

expert

Which option causes a compilation error due to return type mismatch?

Which of the following Java methods will cause a compilation error because the return type does not match the returned value?

A public static int getNumber() { return 3.14; }

B public static double getDouble() { return 3.14; }

C public static String getText() { return "Hello"; }

D public static boolean isTrue() { return true; }