Method parameters in Java - Practice Problems & Coding Challenges

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Challenge - 5 Problems

💻 code output

intermediate

Output of method with primitive parameter modification

What is the output of the following Java code?

Java

public class Test {
    public static void modify(int x) {
        x = x + 10;
    }
    public static void main(String[] args) {
        int a = 5;
        modify(a);
        System.out.println(a);
    }
}

A 5

B 15

C Compilation error

D Runtime error

💻 code output

intermediate

Output of method with object parameter modification

What is the output of this Java program?

Java

class Box {
    int value;
    Box(int v) { value = v; }
}
public class Test {
    public static void modify(Box b) {
        b.value = 10;
    }
    public static void main(String[] args) {
        Box box = new Box(5);
        modify(box);
        System.out.println(box.value);
    }
}

A 10

B Runtime error

C Compilation error

D 5

💻 code output

advanced

Output of method with varargs parameter

What will be printed when this Java code runs?

Java

public class Test {
    public static int sum(int... numbers) {
        int total = 0;
        for (int n : numbers) {
            total += n;
        }
        return total;
    }
    public static void main(String[] args) {
        System.out.println(sum(1, 2, 3));
    }
}

A Runtime error

B 123

C Compilation error

D 6

💻 code output

advanced

Output of method with overloaded parameters

What is the output of this Java program?

Java

public class Test {
    public static void print(int x) {
        System.out.println("int: " + x);
    }
    public static void print(String x) {
        System.out.println("String: " + x);
    }
    public static void main(String[] args) {
        print(5);
        print(null);
    }
}

A Compilation error

B int: 5\nString: null

C int: 5\nRuntime error

D int: 5\nCompilation error

💻 code output

expert

Output of method with final parameter and reassignment attempt

What happens when this Java code runs?

Java

public class Test {
    public static void modify(final int x) {
        // x = x + 1; // Uncommenting this line causes what?
        System.out.println(x);
    }
    public static void main(String[] args) {
        modify(5);
    }
}

A Runtime error

B Compilation error due to reassignment of final parameter

C Prints 5

D Prints 6