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https://github.com/gradle/dpeuni-gradle-intro-devs-deps

Hands-on exercise for DPE University
https://github.com/gradle/dpeuni-gradle-intro-devs-deps

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Hands-on exercise for DPE University

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README 

        
# DPE University Training










## Gradle Dependency Management Exercise



This is a hands-on exercise to go along with the

[Introduction to Gradle Build Tool for Developers](https://dpeuniversity.gradle.com/app/courses/012de84f-fcd3-45d4-9c4c-284382eb3f3f)

training module. In this exercise you will go over the following:



* See dependencies for a project

* Adding dependencies

* Examining dependency conflict resolution



---

## Prerequisites



* Completed the first and second hands-on exercise

* You can perform the exercises in the same Gradle project used in previous exercises



---

## See Dependencies for a Project



1. Open the terminal run

   `./gradlew :app:dependencies`. You will see dependencies grouped by

   configurations.










2. To see the dependencies of just the runtimeClasspath configuration run

   `./gradlew :app:dependencies --configuration=runtimeClasspath`










---

## Adding Dependencies



Let's add some more functionality to our application. Currently it only prints

a greeting message. Let's make it fetch some data from a url and print it. We

will use the [Google Http Client](https://github.com/googleapis/google-http-java-client)

for this.



We need to get the Gradle dependency statement for this library. Follow the

steps below to get this:



1. Go to [https://mvnrepository.com/](https://mvnrepository.com/)



2. In the search bar type `google http client`



3. One of the top results will be `com.google.http-client » google-http-client`,

   click on it, and then click on the `1.44.1` version



4. Click on the `Gradle (Kotlin)` tab



5. Copy just the module ID and version, not the dependency configuration










6. Open the version catalog file which is `gradle/libs.versions.toml`



7. Under the `libraries` section, add an entry called `google-http-client` and set it to the copied contents:



```toml

google-http-client = "com.google.http-client:google-http-client:1.44.1"

```



8. If using IntelliJ, hit the Gradle refresh icon










9. In `app/build.gradle.kts`, in the `dependencies` section add an `implementation` dependency to `libs.google.http.client`. Notice that instead of dashes you will use dots:



```

implementation(libs.google.http.client)

```



10. Run `./gradlew :app:dependencies --configuration=runtimeClasspath` again

    and notice the additional dependencies - both direct and transitive.










---

## Examining Dependency Conflict Resolution



1. Notice in the dependencies, the `google-http-client` library depends on

   `guava`, which is also a direct dependency.










2. The `guava` version `google-http-client` depends on is older than the

   version in the direct dependency, so you will see Gradle handles the

   conflict by using the highest version of the `guava` library.










---

## Update Application



1. Open the `app/src/main/java/com/gradle/lab/App.java` file and replace the

   contents *after the package declaration* with the following:



```java

import com.google.api.client.http.GenericUrl;

import com.google.api.client.http.HttpRequest;

import com.google.api.client.http.HttpRequestFactory;

import com.google.api.client.http.javanet.NetHttpTransport;



import java.io.IOException;



public class App {

    public String getGreeting() {

        return "Hello World!";

    }



    public String getUrl() {

        // This is a small website and easily prints.

        return "https://wiby.me/";

    }



    public static void main(String[] args) throws IOException {

        App app = new App();

        System.out.println(app.getGreeting());



        HttpRequestFactory requestFactory = new NetHttpTransport().createRequestFactory();

        HttpRequest request = requestFactory.buildGetRequest(new GenericUrl(app.getUrl()));

        String rawResponse = request.execute().parseAsString();

        System.out.println("\n---------\n");

        System.out.println(rawResponse);

    }

}

```



2. Then open the terminal and execute `./gradlew :app:run`, notice the website

   contents are also printed.










---

## Solution Reference



If you get stuck you can refer to the project files in this repository.