initialize a java dockerfile

Dockerfile

@@ -1,23 +1,41 @@
-# Stage 1: Build Spring Boot app with Maven
+# Stage 1: Generate and build Spring Boot app
 FROM maven:3.9.6-eclipse-temurin-17 AS build
 WORKDIR /app
 
-# Copy project files
-COPY pom.xml .
-COPY src ./src
+# Create a minimal pom.xml
+RUN printf '<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/xsd/maven-4.0.0.xsd"> \
+  <modelVersion>4.0.0</modelVersion> \
+  <groupId>com.example</groupId> \
+  <artifactId>springboot-hf</artifactId> \
+  <version>0.0.1-SNAPSHOT</version> \
+  <parent><groupId>org.springframework.boot</groupId> \
+  <artifactId>spring-boot-starter-parent</artifactId> \
+  <version>3.2.5</version></parent> \
+  <dependencies><dependency> \
+  <groupId>org.springframework.boot</groupId> \
+  <artifactId>spring-boot-starter-web</artifactId> \
+  </dependency></dependencies> \
+  <build><plugins><plugin> \
+  <groupId>org.springframework.boot</groupId> \
+  <artifactId>spring-boot-maven-plugin</artifactId> \
+  </plugin></plugins></build></project>' > pom.xml
 
-# Build the Spring Boot JAR (skip tests to save time)
+# Create minimal Hello World application
+RUN mkdir -p src/main/java/com/example/demo && \
+  printf 'package com.example.demo;\n\nimport org.springframework.boot.SpringApplication;\nimport org.springframework.boot.autoconfigure.SpringBootApplication;\nimport org.springframework.web.bind.annotation.GetMapping;\nimport org.springframework.web.bind.annotation.RestController;\n\n@SpringBootApplication\n@RestController\npublic class DemoApplication {\n  public static void main(String[] args) {SpringApplication.run(DemoApplication.class, args);} \n\n  @GetMapping("/")\n  public String hello(){return "Hello from Spring Boot on Hugging Face Spaces 🚀";}\n}' > src/main/java/com/example/demo/DemoApplication.java
+
+# Build the jar
 RUN mvn clean package -DskipTests
 
 # Stage 2: Run the app
 FROM openjdk:17-jdk-slim
 WORKDIR /app
-
-# Copy the JAR from the build stage
 COPY --from=build /app/target/*.jar app.jar
 
-# Hugging Face Spaces requires exposing port 7860
+# Hugging Face requires port 7860
 EXPOSE 7860
 
-# Run Spring Boot on port 7860
 ENTRYPOINT ["java","-jar","app.jar","--server.port=7860"]