Build tools (Maven, Gradle, npm) in Jenkins - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Maven build command?

You run the following command in a Jenkins pipeline:

mvn clean install -DskipTests

What will be the main effect of this command?

Jenkins

mvn clean install -DskipTests

A It cleans the project, compiles the code, packages it, and skips running tests.

B It only runs the tests without building the project.

C It installs dependencies but does not compile or package the project.

D It cleans the project and runs tests but does not package the code.

💡 Hint

The 'clean' phase removes previous build files, 'install' compiles and packages, and '-DskipTests' skips tests.

The 'mvn clean install' command cleans old files, compiles, runs tests, and packages the project. Adding '-DskipTests' skips the test execution but still compiles and packages.

❓ Configuration

intermediate

Which Gradle build script snippet correctly applies the Java plugin and sets the Java version to 17?

Choose the correct Gradle build script snippet to apply the Java plugin and set the Java source and target compatibility to version 17.

A

plugins {
    id 'java'
}

java {
    sourceCompatibility = '17'
    targetCompatibility = '17'
}

B

plugins {
    id 'java'
}

java {
    sourceCompatibility = JavaVersion.VERSION_17
    targetCompatibility = JavaVersion.VERSION_17
}

C

apply plugin: 'java'

sourceCompatibility = '1.7'
targetCompatibility = '1.7'

D

apply plugin: 'java'

java {
    sourceCompatibility = JavaVersion.VERSION_1_7
    targetCompatibility = JavaVersion.VERSION_1_7
}

💡 Hint

Use JavaVersion constants for version 17 and the plugins block for modern Gradle scripts.

Option B uses the plugins block and sets source and target compatibility to JavaVersion.VERSION_17, which is correct for Java 17. Other options either use old syntax or wrong versions.

🔀 Workflow

advanced

In a Jenkins pipeline, which npm command sequence correctly installs dependencies and runs tests with coverage?

You want to install npm dependencies and then run tests with coverage reporting in a Jenkins pipeline. Which command sequence is correct?

A npm install && npm run test:coverage

B npm run test:coverage && npm install

C npm test && npm install

D npm install test:coverage

💡 Hint

Dependencies must be installed before running tests.

Option A installs dependencies first, then runs the test script with coverage. Option A runs tests before installing, which fails. Option A runs tests without coverage and installs after. Option A is invalid syntax.

❓ Troubleshoot

advanced

What error will this Maven command produce if the pom.xml file is missing?

You run this command in a Jenkins job:

mvn clean package

But the pom.xml file is missing in the workspace. What error will Maven show?

Jenkins

mvn clean package

A [ERROR] Could not find the 'package' command.

B [ERROR] Missing Java compiler version in pom.xml.

C [ERROR] The goal you specified requires a project to execute but there is no POM in this directory.

D [ERROR] Network connection failed while downloading dependencies.

💡 Hint

Maven requires a pom.xml file to run goals like clean or package.

Without pom.xml, Maven cannot find project info and shows error about missing POM. Other errors relate to different issues.

✅ Best Practice

expert

Which npm script configuration in package.json ensures tests run only after dependencies are installed in Jenkins?

You want to configure your package.json scripts so that running npm run ci-test in Jenkins installs dependencies and then runs tests. Which scripts section is correct?

Jenkins

{
  "scripts": {
    "install": "npm install",
    "test": "jest",
    "ci-test": "???"
  }
}

A "ci-test": "npm test"

B "ci-test": "npm test && npm install"

C "ci-test": "npm install; npm test"

D "ci-test": "npm install && npm test"

💡 Hint

Tests should run after dependencies are installed; use && to chain commands.

Option D runs 'npm install' first, then 'npm test'. Option D runs tests before install, which can fail. Option D uses semicolon which works but is less safe in cross-platform scripts. Option D skips install.