Spring Data JPA + EclipseLink: Configure Spring Boot with EclipseLink JPA

dependencies {
  implementation ('org.eclipse.persistence:eclipselink:2.7.7')
  implementation ('org.springframework.boot:spring-boot-starter-web')
  implementation('org.springframework.boot:spring-boot-starter-actuator')
  implementation('org.springframework.boot:spring-boot-starter-data-jpa'){
    exclude group: 'org.hibernate', module: 'hibernate-core'
    exclude group: 'org.hibernate.common', module: 'common-annotations'
  }
    //...Your project dependencies...
}

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories("com.marcnuri.demo.springeclipselink.repository")
public class CustomJpaConfiguration extends JpaBaseConfiguration {

  protected CustomJpaConfiguration(DataSource dataSource, JpaProperties properties,
    ObjectProvider<JtaTransactionManager> jtaTransactionManager) {
    super(dataSource, properties, jtaTransactionManager);
  }

  @Override
  protected AbstractJpaVendorAdapter createJpaVendorAdapter() {
    return new EclipseLinkJpaVendorAdapter();
  }

  @Override
  protected Map<String, Object> getVendorProperties() {
    final Map<String, Object> ret = new HashMap<>();
    ret.put(PersistenceUnitProperties.BATCH_WRITING, BatchWriting.JDBC);
    return ret;
  }

  @Bean("entityManagerFactory")
  public LocalContainerEntityManagerFactoryBean localContainerEntityManagerFactory(
    EntityManagerFactoryBuilder builder, DataSource dataSource) {

    return builder
      .dataSource(dataSource)
      .packages("com.marcnuri.demo.springeclipselink.repository")
      .persistenceUnit("YourPersistenceUnitName")
      .properties(initJpaProperties()).build();
  }

  @Bean
  public static DataSource dataSource() {
    final DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName("org.h2.Driver");
    dataSource.setUrl("jdbc:h2:mem:marcnuridemo;DB_CLOSE_DELAY=-1");
    dataSource.setUsername("sa");
    dataSource.setPassword("password");
    return dataSource;
  }

  @Bean
  public static PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
    final JpaTransactionManager transactionManager = new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(emf);
    return transactionManager;
  }

  @Bean
  @Primary
  public static JpaProperties properties() {
    final JpaProperties jpaProperties = new JpaProperties();
    jpaProperties.setShowSql(true);
    jpaProperties.setDatabasePlatform("org.eclipse.persistence.platform.database.H2Platform");
    return jpaProperties;
  }

  private static Map<String, ?> initJpaProperties() {
    final Map<String, Object> ret = new HashMap<>();
    // Add any JpaProperty you are interested in and is supported by your Database and JPA implementation
    ret.put(PersistenceUnitProperties.BATCH_WRITING, BatchWriting.JDBC);
    ret.put(PersistenceUnitProperties.LOGGING_LEVEL, SessionLog.FINEST_LABEL);
    ret.put(PersistenceUnitProperties.WEAVING, "false");
    ret.put(PersistenceUnitProperties.DDL_GENERATION, PersistenceUnitProperties.CREATE_ONLY);
    ret.put(PersistenceUnitProperties.DDL_GENERATION_MODE, PersistenceUnitProperties.DDL_DATABASE_GENERATION);
    return ret;
  }
}

@Bean
public DataSource dataSource() {
  //In classpath from spring-boot-starter-web
  final Properties pool = new Properties();
  pool.put("driverClassName", "org.postgresql.Driver");
  pool.put("url", "jdbc:postgresql://example.com:5432/DatabaseName");
  pool.put("username", "user");
  pool.put("password", "password");
  pool.put("minIdle", 1);
  return new org.apache.tomcat.jdbc.pool.DataSourceFactory().createDataSource(pool);
}