Implement REST API with JWT authentication based on design specifications

.gitignore

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+# Maven
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+.mvn/wrapper/maven-wrapper.jar
+
+# IDEs
+.idea/
+*.iws
+*.iml
+*.ipr
+.vscode/
+.classpath
+.project
+.settings/
+
+# OS
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Logs
+*.log
+
+# Other
+.env
+.env.local
+.env.*.local

README.md

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-# coding-agent-output-comparison
+# User Management REST API
+
+REST API for user management with JWT authentication based on the provided specifications.
+
+## Features
+
+- **Endpoint:** `GET /api/users/{id}`
+- **Authentication:** JWT token required
+- **Authorization:** Admin role only
+- **Response:** JSON with user data (id, name, email, role)
+- **Error Handling:** Proper HTTP status codes (200, 401, 403, 404)
+
+## Technical Stack
+
+- **Framework:** Spring Boot 3.1.5
+- **Java Version:** 17
+- **Security:** JWT tokens with HMAC-SHA384 signing
+- **Database:** H2 in-memory
+- **ORM:** JPA/Hibernate
+
+## Quick Start
+
+### 1. Build and Run
+
+```bash
+# Build and run the application
+mvn spring-boot:run
+```
+
+The API will start on `http://localhost:8080`
+
+### 2. Generate JWT Tokens
+
+```bash
+# Generate test tokens
+mvn spring-boot:run -Dspring-boot.run.profiles=token-gen
+```
+
+This will output admin and user tokens for testing.
+
+### 3. Test API Endpoints
+
+```bash
+# Test with admin token (replace {admin-token} with actual token)
+curl -H "Authorization: Bearer {admin-token}" http://localhost:8080/api/users/1
+
+# Test without token (should return 403)
+curl http://localhost:8080/api/users/1
+
+# Test with non-existent user (should return 404)
+curl -H "Authorization: Bearer {admin-token}" http://localhost:8080/api/users/999
+```
+
+## API Documentation
+
+### GET /api/users/{id}
+
+Retrieve user by ID (Admin only).
+
+**Parameters:**
+- `id` (path) - User ID (Long, required)
+
+**Headers:**
+- `Authorization: Bearer {jwt-token}` (required)
+
+**Responses:**
+
+- **200 OK** - User found and returned
+```json
+{
+  "id": 1,
+  "name": "Admin User",
+  "email": "admin@example.com", 
+  "role": "ADMIN"
+}
+```
+
+- **401 Unauthorized** - Missing or invalid JWT token
+- **403 Forbidden** - Insufficient permissions (non-admin user)
+- **404 Not Found** - User not found
+```json
+{
+  "error": "Not Found",
+  "message": "User not found with id: 999",
+  "timestamp": "2025-09-02T07:00:00.000",
+  "status": 404
+}
+```
+
+## Test Data
+
+The application automatically loads test data:
+
+1. **ID: 1** - Admin User (admin@example.com, ADMIN)
+2. **ID: 2** - Regular User (user@example.com, USER)  
+3. **ID: 3** - Test User (test@example.com, USER)
+
+## Database Console
+
+For development, H2 console is available at: `http://localhost:8080/h2-console`
+
+- **JDBC URL:** `jdbc:h2:mem:testdb`
+- **Username:** `sa`
+- **Password:** (empty)

pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.1.5</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.example</groupId>
+    <artifactId>user-api</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <name>User API</name>
+    <description>REST API for user management with JWT authentication</description>
+
+    <properties>
+        <java.version>17</java.version>
+        <jwt.version>0.11.5</jwt.version>
+    </properties>
+
+    <dependencies>
+        <!-- Spring Boot Starters -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+
+        <!-- JWT -->
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-api</artifactId>
+            <version>${jwt.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-impl</artifactId>
+            <version>${jwt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-jackson</artifactId>
+            <version>${jwt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <!-- Database -->
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+
+        <!-- Test -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

src/main/java/com/example/userapi/UserApiApplication.java

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+package com.example.userapi;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class UserApiApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(UserApiApplication.class, args);
+    }
+}

src/main/java/com/example/userapi/config/DataLoader.java

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+package com.example.userapi.config;
+
+import com.example.userapi.entity.User;
+import com.example.userapi.repository.UserRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Component;
+
+@Component
+@Profile("!test")
+public class DataLoader implements CommandLineRunner {
+
+    @Autowired
+    private UserRepository userRepository;
+
+    @Override
+    public void run(String... args) throws Exception {
+        // Only load data if the repository is empty
+        if (userRepository.count() == 0) {
+            userRepository.save(new User("Admin User", "admin@example.com", "ADMIN"));
+            userRepository.save(new User("Regular User", "user@example.com", "USER"));
+            userRepository.save(new User("Test User", "test@example.com", "USER"));
+        }
+    }
+}

src/main/java/com/example/userapi/controller/UserController.java

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+package com.example.userapi.controller;
+
+import com.example.userapi.dto.UserResponse;
+import com.example.userapi.entity.User;
+import com.example.userapi.exception.UserNotFoundException;
+import com.example.userapi.repository.UserRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/users")
+public class UserController {
+
+    @Autowired
+    private UserRepository userRepository;
+
+    @GetMapping("/{id}")
+    @PreAuthorize("hasRole('ADMIN')")
+    public ResponseEntity<UserResponse> getUserById(@PathVariable Long id) {
+        User user = userRepository.findById(id)
+                .orElseThrow(() -> new UserNotFoundException(id));
+
+        UserResponse response = new UserResponse(
+                user.getId(),
+                user.getName(),
+                user.getEmail(),
+                user.getRole()
+        );
+
+        return ResponseEntity.ok(response);
+    }
+}

src/main/java/com/example/userapi/dto/UserResponse.java

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+package com.example.userapi.dto;
+
+public class UserResponse {
+    private Long id;
+    private String name;
+    private String email;
+    private String role;
+
+    // Constructors
+    public UserResponse() {}
+
+    public UserResponse(Long id, String name, String email, String role) {
+        this.id = id;
+        this.name = name;
+        this.email = email;
+        this.role = role;
+    }
+
+    // Getters and Setters
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getRole() {
+        return role;
+    }
+
+    public void setRole(String role) {
+        this.role = role;
+    }
+}