Project structure and build basics in Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Understanding Kotlin source folder structure

Given a typical Kotlin project, where should you place your main application code?

A src/main/kotlin

B src/test/kotlin

C build/kotlin

D lib/kotlin

💡 Hint

Main application code goes in the source folder for production code, not tests or build outputs.

The src/main/kotlin folder is the standard place for Kotlin source files that make up the main application. Test code goes under src/test/kotlin. The build folder contains compiled outputs, and lib is not a standard source folder.

❓ Predict Output

intermediate

Gradle build script basics

What will be the output of running gradle tasks in a Kotlin project with a standard Gradle build?

A Lists all available Gradle tasks including build, clean, and test

B Compiles the Kotlin source code

C Runs the main application

D Deletes the build directory

💡 Hint

Think about what the tasks command does in Gradle.

The gradle tasks command lists all the tasks available in the project. It does not perform compilation, execution, or cleaning by itself.

🔧 Debug

advanced

Identify the build error in Gradle Kotlin DSL

Consider this snippet from a build.gradle.kts file:

plugins {
    kotlin("jvm") version "1.5.0"
}

repositories {
    mavenCentral()
}

dependencies {
    implementation(kotlin("stdlib"))
    testImplementation("junit:junit:4.13.2")
}

application {
    mainClass.set("com.example.MainKt")
}

What error will Gradle report when trying to build?

A Error: Missing repository declaration

B Error: Kotlin version mismatch

C Error: Unresolved reference: application

D No error, build succeeds

💡 Hint

Check if the application block is recognized by Gradle without applying the right plugin.

The application block requires the application plugin to be applied. Since it is missing, Gradle will report an unresolved reference error for application.

❓ Predict Output

advanced

Output of Kotlin main function in Gradle project

Given this Kotlin main function in src/main/kotlin/com/example/Main.kt:

package com.example

fun main() {
    println("Hello from Kotlin Gradle project!")
}

What is the output when you run gradle run after configuring the application plugin correctly?

A Build successful, no output

B Hello from Kotlin Gradle project!

C Error: main function not found

D Gradle task 'run' not found

💡 Hint

Running gradle run executes the main function if configured properly.

With the application plugin and mainClass set, gradle run executes the main function and prints the message.

🧠 Conceptual

expert

Understanding Gradle build lifecycle phases

Which Gradle build phase is responsible for compiling Kotlin source code?

A Execution phase

B Configuration phase

C Initialization phase

D Task execution phase

💡 Hint

Think about when tasks actually run during a Gradle build.

Gradle has three main phases: initialization, configuration, and task execution. The compilation happens during the task execution phase when the compileKotlin task runs.