How to Make a Project Using Spring Boot, MySQL, Spring Data JPA, and Maven?

import javax.persistence.EntityManagerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalEntityManagerFactoryBean;

@Configuration 
// Scan the repositories that is present under com.gfg.jpa
@EnableJpaRepositories(basePackages = {"com.gfg.jpa"})
public class ContestAppConfig {
    @Bean
    // LocalEntityManagerFactoryBean sets up an EntityManagerFactory to work with GeeksDB
    public LocalEntityManagerFactoryBean entityManagerFactory() {
        LocalEntityManagerFactoryBean factoryBean = new LocalEntityManagerFactoryBean();
        factoryBean.setPersistenceUnitName("GeeksDB");        
        return factoryBean;
    }
    
    @Bean
    // Transaction manager for the configured EntityManagerFactory,
    public JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory);        
        return transactionManager;
    }    
}

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

// It maps with db table Contest
@Entity
public class Contest {
    // The @Id and @GeneratedValue annotations map 
      // the field id to the primary key column of the table. 
      // Suppose that all the fields of the class have
      // same name as the column names in the database table.
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String contestName;
    private String contestDescription;

    protected Contest() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }
    
    public String getContestName() {
        return contestName;
    }

    public void setContestName(String contestName) {
        this.contestName = contestName;
    }

    public String getContestDescription() {
        return contestDescription;
    }

    public void setContestDescription(String contestDescription) {
        this.contestDescription = contestDescription;
    }

    @Override
    public String toString() {
        return "Contest [contestName=" + contestName + ", contestDescription=" + contestDescription + "]";
    }

}

import java.util.List;
import org.springframework.data.repository.CrudRepository;

public interface ContestRepository extends CrudRepository<Contest, Long> {
    // We can add the required methods here
    List<Contest> findByContestName(String contestName);
}

import java.util.List;
import java.util.Optional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service("contestService")
public class ContestService {
  
    @Autowired
    private ContestRepository contestRepository;
    
    public void test() {
        // Save a new contest
        Contest geekContest = new Contest();
        geekContest.setContestName("PremierLeague");
        geekContest.setContestDescription("Inviting Geeks To submit articles in plenty");
        
        contestRepository.save(geekContest);
        
        // Find a contest by ID
        Optional<Contest> result = contestRepository.findById(1L);
        result.ifPresent(contest -> System.out.println(contest));
        
        // Find contest by contest name
        List<Contest> contests = contestRepository.findByContestName("PremierLeague");
        contests.forEach(contest -> System.out.println(contest));
        
        // List all contests
        Iterable<Contest> iterator = contestRepository.findAll();
        iterator.forEach(contest -> System.out.println(contest));
        
        // Count number of contest
        long countOfContest = contestRepository.count();
        System.out.println("Number of contest held: " + countOfContest);
    }
}

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class ContestTest {
  
    public static void main(String[] args) {
      
        AnnotationConfigApplicationContext appContext = new AnnotationConfigApplicationContext();
        appContext.scan("com.gfg.jpa");
        appContext.refresh();

        ContestService contestService = (ContestService) appContext.getBean("contestService");
        contestService.test();

        appContext.close();
      
    }

}