Initial commit

pom.xml

+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>ch.hepia</groupId>
+  
+  <artifactId>my-project</artifactId>
+  
+  <packaging>jar</packaging>
+  <version>0.1</version>
+  <url>http://maven.apache.org</url>
+  
+  <properties>
+    <maven.compiler.source>11</maven.compiler.source>
+    <maven.compiler.target>11</maven.compiler.target>
+  </properties>
+  
+  <dependencies>
+    <dependency>
+        <groupId>org.junit.jupiter</groupId>
+        <artifactId>junit-jupiter-engine</artifactId>
+        <version>5.2.0</version>
+        <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>javax.json</groupId>
+      <artifactId>javax.json-api</artifactId>
+      <version>1.1.4</version>
+    </dependency>
+    <dependency>
+      <groupId>org.glassfish</groupId>
+      <artifactId>javax.json</artifactId>
+      <version>1.1</version>
+    </dependency>
+    <dependency>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <version>2.8.5</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+    
+      <!-- The plugin provides 2 goals to help execute system and Java programs. -->
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>1.6.0</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>java</goal>
+            </goals>
+          </execution>
+        </executions>
+        <configuration>
+          <mainClass>ch.hepia.App</mainClass>
+          <cleanupDaemonThreads>false</cleanupDaemonThreads>
+        </configuration>
+      </plugin>
+      
+      <!-- The Surefire Plugin is used during the test phase of the build lifecycle 
+           to execute the unit tests of an application -->
+      <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.22.0</version>
+      </plugin>
+      
+      <!-- Used to create a jar with all dependencies (mvn package will create it) -->
+      <plugin>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <version>3.1.0</version>
+        <configuration>
+          <descriptorRefs>
+            <descriptorRef>jar-with-dependencies</descriptorRef>
+          </descriptorRefs>
+        </configuration>
+        <executions>
+          <execution>
+            <id>make-assembly</id>            <!-- this is used for inheritance merges -->
+            <phase>package</phase>            <!-- bind to the packaging phase -->
+            <goals>
+              <goal>single</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      
+    </plugins>
+  </build>
+
+</project>

src/main/java/ch/hepia/App.java

+package ch.hepia;
+import javax.json.*;
+import java.io.*;
+
+public class App {
+
+  public App() {
+
+    ClassLoader classLoader = getClass().getClassLoader();
+    var url = classLoader.getResource("orders.json");
+    File file = new File(url.getFile());
+                            
+    try(InputStream input = new FileInputStream(file)) {
+      JsonReader reader = Json.createReader(input);
+      JsonArray orders = reader.readArray();
+
+      // List without duplicates :
+      orders.stream() // Stream<JsonValue>
+            .flatMap(
+              o -> o.asJsonObject().getJsonArray("vendors").stream().map( v -> v.asJsonObject().getString("slug"))
+            ) // Stream<String> (slugs)
+            .distinct() // Stream<String> without duplicates
+            .forEach(System.out::println); // void
+
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+  }
+  public static void main(String[] args) {
+    new App();
+  }
+}