Javalin setup

Dockerfile

@@ -1,16 +1,5 @@
-FROM maven:3.9.4-eclipse-temurin-17 AS build
-WORKDIR /app
-
-# Copy pom and source code
-COPY pom.xml .
-COPY src ./src
-
-# Build the jar
-RUN mvn clean package -DskipTests
-
-# Run stage
 FROM eclipse-temurin:17-jre
 WORKDIR /app
-COPY --from=build /app/target/demo-0.0.1-SNAPSHOT.jar app.jar
-EXPOSE 8080
+COPY target/javalin-demo-0.0.1-SNAPSHOT.jar app.jar
+EXPOSE 7860
 ENTRYPOINT ["java", "-jar", "app.jar"]

pom.xml

@@ -1,46 +1,55 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" 
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
                              http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.example</groupId>
-    <artifactId>demo</artifactId>
+    <artifactId>javalin-demo</artifactId>
     <version>0.0.1-SNAPSHOT</version>
-    <packaging>jar</packaging>
-
-    <name>springboot-hf</name>
-    <description>Spring Boot HF Space Example</description>
-
-    <parent>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-parent</artifactId>
-        <version>3.2.5</version>
-        <relativePath/>
-    </parent>
-
     <properties>
         <java.version>17</java.version>
     </properties>
 
     <dependencies>
-        <!-- Spring Boot Web -->
+        <!-- Javalin -->
         <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-web</artifactId>
+            <groupId>io.javalin</groupId>
+            <artifactId>javalin-bundle</artifactId>
+            <version>5.6.1</version>
         </dependency>
-        
-        <!-- Optional: for JSON serialization -->
+
+        <!-- JSON serialization -->
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
+            <version>2.16.4</version>
         </dependency>
     </dependencies>
 
     <build>
         <plugins>
+            <!-- Package JAR -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>${java.version}</source>
+                    <target>${java.version}</target>
+                </configuration>
+            </plugin>
+
             <plugin>
-                <groupId>org.springframework.boot</groupId>
-                <artifactId>spring-boot-maven-plugin</artifactId>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.3.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <mainClass>DemoApplication</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
             </plugin>
         </plugins>
     </build>

src/DemoApplication.java

@@ -0,0 +1,15 @@
+import io.javalin.Javalin;
+
+public class DemoApplication {
+
+    public static void main(String[] args) {
+        // Hugging Face provides the port via environment variable
+        int port = Integer.parseInt(System.getenv().getOrDefault("PORT", "8080"));
+
+        Javalin app = Javalin.create().start(port);
+
+        app.get("/user", ctx -> {
+            ctx.json(new User("Kevan", 21));
+        });
+    }
+}

src/User.java

@@ -0,0 +1,9 @@
+public class User {
+    public String name;
+    public int age;
+
+    public User(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+}

src/main/java/com/example/demo/DemoApplication.java

@@ -1,20 +0,0 @@
-package com.example.demo;
-
-import org.springframework.boot.SpringApplication;
-import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.RestController;
-
-@SpringBootApplication
-@RestController
-public class DemoApplication {
-
-    @GetMapping("/user")
-    public User getUser() {
-        return new User("Kevan", 21);
-    }
-
-    public static void main(String[] args) {
-        SpringApplication.run(DemoApplication.class, args);
-    }
-}

src/main/java/com/example/demo/User.java

@@ -1,19 +0,0 @@
-package com.example.demo;
-
-public class User {
-    private String name;
-    private int age;
-
-    public User() {}
-
-    public User(String name, int age) {
-        this.name = name;
-        this.age = age;
-    }
-
-    public String getName() { return name; }
-    public void setName(String name) { this.name = name; }
-
-    public int getAge() { return age; }
-    public void setAge(int age) { this.age = age; }
-}

target/maven-archiver/pom.properties

@@ -1,3 +0,0 @@
-artifactId=springboot-hf
-groupId=com.example
-version=0.0.1-SNAPSHOT