Generate Swagger UI for Spring Boot REST APIs

package xyz.bijit.swagger;
public class Tweet {

    // Unique identifier for the tweet
    private Integer id;

    // Title or headline of the tweet
    private String title;

    // Content/message of the tweet
    private String msg;

    // Getter method for tweet ID
    public Integer getId() { return id; }

    // Setter method for tweet ID
    public void setId(Integer id) { this.id = id; }

    // Getter method for tweet title
    public String getTitle() { return title; }

    // Setter method for tweet title
    public void setTitle(String title)
    {
        this.title = title;
    }

    // Getter method for tweet message/content
    public String getMsg() { return msg; }

    // Setter method for tweet message/content
    public void setMsg(String msg) { this.msg = msg; }
}

package xyz.bijit.swagger;

import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Service;

@Service // Marks this class as a Spring service component
         // (auto-detected by component scanning)
         public class TweetService {

    // In-memory list to store tweet objects
    private List<Tweet> tweetList = new ArrayList<>();

    public void addTweet()
    {
        // First dummy tweet
        Tweet tweet = new Tweet();
        tweet.setId(1);
        tweet.setTitle("My first tweet");
        tweet.setMsg(
            "This is a dummy tweet for demonstration purposes.");
        tweetList.add(tweet); // Add to list

        // Second dummy tweet
        Tweet tweet2 = new Tweet();
        tweet2.setId(2);
        tweet2.setTitle("My second tweet");
        tweet2.setMsg(
            "This is the second dummy tweet for demonstration purposes.");
        tweetList.add(tweet2); // Add to list
    }

    /**
     * Returns the list of all tweets.
     * @return List of Tweet objects
     */
    public List<Tweet> getTweets() { return tweetList; }
}

package xyz.bijit.swagger;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

// Marks this class as a REST controller that can handle
// HTTP requests
@RestController
public class TweetController {

    // Injects the TweetService bean to use its business
    // logic methods
    @Autowired private TweetService tweetService;

    // Handles HTTP POST requests to /add and adds a tweet
    // using TweetService
    @PostMapping("/add") public void addTweet()
    {
        tweetService.addTweet(); // Delegates to the service
                                 // to add a sample tweet
    }

    // Handles HTTP GET requests to /view and returns the
    // list of tweets
    @GetMapping("/view") public List<Tweet> viewTweets()
    {
        return tweetService
            .getTweets(); // Delegates to the service to
                          // retrieve tweets
    }

    // Handles HTTP GET requests to /hello and returns a
    // simple greeting message
    @GetMapping("/hello") public String hello()
    {
        return "Hello World!"; // Returns a static string
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

// Marks this class as the main Spring Boot application
@SpringBootApplication

// Enables Swagger 2 for API documentation generation
@EnableSwagger2

// Enables Spring MVC explicitly (sometimes required for
// Swagger UI with SpringFox)
@EnableWebMvc

public class SwaggerApplication {

    // Entry point of the Spring Boot application
    public static void main(String[] args)
    {
        SpringApplication.run(SwaggerApplication.class,
                              args);
    }
}

import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

@Configuration
public class SwaggerConfig {

    public Docket SwaggerApi()
    {
        return new Docket(DocumentationType.SWAGGER_2)
            .select()
            .apis(RequestHandlerSelectors.any())
            .paths(PathSelectors.any())
            .build();
    }