Spring transactional method not working with split thread

I have a Spring application that has a background polling service running on a separate thread to update the state of the data in the database ( EmployeeStatusPollService

). I am using JPA (Hibernate vendor) for a repository. I have implemented this service in two solutions, but only one solution works. Below are two solutions.

Solution 1: A transactional method checkAndUpdateStatus

in another service class and polling service calls it

@Service
public class EmployeeStatusPollService implements Runnable {

  @Inject 
  private EmployeeService employeeService;

  private static final int DEFAULT_PAGE_SIZE = 300;
  private boolean flag = true;

  public EmployeeStatusPollService() {
  }

  @PostConstruct
  public void start() {
    SimpleAsyncTaskExecutor executor = new SimpleAsyncTaskExecutor();
    executor.setConcurrencyLimit(SimpleAsyncTaskExecutor.NO_CONCURRENCY);
    executor.execute(this);
  }

  public void run() { 
    while(flag) {
      try {
        int pagenum = 1;
        List<Employee> items = null;

        do {        
          items = employeeService.checkAndUpdateStatus(pagenum, DEFAULT_PAGE_SIZE);
        } while(items != null && items.size() == DEFAULT_PAGE_SIZE);      
      } catch(Exception ex) {

      }
    }
  }
}

@Service
public class EmployeeServiceImpl implements EmployeeService {

  private static final Logger LOG = LoggerFactory.getLogger(EmployeeServiceImpl.class);

  @Inject 
  private EmployeeRepository employeeRepository;

  @Transactional
    public List<Employee> checkAndUpdateStatus(int pagenum, int pagesize) throws Exception {
    // ....
  }
}

      

        
        
        
      

    

Solution 2: The transactional method checkAndUpdateStatus

is in the polling service class

@Service
public class EmployeeStatusPollService implements Runnable {

  @Inject 
  private EmployeeRepository employeeRepository;

  private static final int DEFAULT_PAGE_SIZE = 300;
  private boolean flag = true;

  public EmployeeStatusPollService() {
  }

  @PostConstruct
  public void start() {
    SimpleAsyncTaskExecutor executor = new SimpleAsyncTaskExecutor();
    executor.setConcurrencyLimit(SimpleAsyncTaskExecutor.NO_CONCURRENCY);
    executor.execute(this);
  }

  public void run() { 
    while(flag) {
      try {
        int pagenum = 1;
        List<Employee> items = null;

        do {        
          items = checkAndUpdateStatus(pagenum, DEFAULT_PAGE_SIZE);
        } while(items != null && items.size() == DEFAULT_PAGE_SIZE);      
      } catch(Exception ex) {

      }
    }
  }

  @Transactional
    public List<Employee> checkAndUpdateStatus(int pagenum, int pagesize) throws Exception {
    // ....
  }
}

      

        
        
        
      

    

Method Details checkAndUpdateStatus

@Transactional
public List<Employee> checkAndUpdateStatus(int pagenum, int pagesize) throws Exception {
  PageRequest page = new PageRequest(pagenum, pagesize);
  Page<Employee> pagedItems = employeeRepository.findByStatus(EmployeeStatus.PENDING, page);  // Line 1: Query employees 
  List<Employee> emps = pagedItems.getContent();      
  List<Long> updatedItems = new ArrayList<>();
  int i = 0;

  for(Employee emp:emps) {
    try {
      // ...

      emp.setStatus(status);  // Line 2: Update employee status
      employeeRepository.save(emp); // Line 3: Save/Update employee
      updatedItems.add(emp.getId());
      i++;

      if(i % 50 == 0) {
        employeeRepository.flush(); // Line 4: flush for every 50 employees
      }

      //....        
    } catch (Exception ex) {    
      // handle exception here....
    }
  }

  return emps;
}

      

        
        
        
      

    

Configuration

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
    <property name="driverClassName" value="${jdbc.driver}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
    <property name="defaultAutoCommit" value="false" />
</bean>

<bean id="entityManager" class="org.springframework.orm.jpa.support.SharedEntityManagerBean">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource"></property>
    <property name="jpaDialect" ref="jpaDialect"></property>
    <property name="jpaVendorAdapter" ref="jpaVendorAdapter"></property>
    <property name="packagesToScan" value="${jpa.packagesToScan}" />
    <property name="jpaProperties">
        <props>
            <prop key="hibernate.dialect">${hibernate.dialect}</prop>
            <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
            <prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
            <prop key="hibernate.connection.autocommit">${hibernate.connection.autocommit}</prop>
            <prop key="hibernate.connection.defaultAutoCommit">${hibernate.connection.defaultAutoCommit}</prop>
        </props>
    </property>
</bean>

<bean id="jpaDialect" class="org.springframework.orm.jpa.vendor.HibernateJpaDialect"></bean>

<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"></bean>

      

        
        
        
      

    

Solution 2 doesn't work and I get the "Persistent entity is being detached ..." error when it updates / saves the object in the database on line 3 of the method checkAndUpdateStatus

.

IMO solution 2 doesn't work because the method checkAndUpdateStatus

doesn't fit in the Transactional Context even though it's flagged @Transactional

. Even when I installed REQUIRES_NEW

it still doesn't work. Can anyone explain to me about this error why this happened, or send me some help documentation about this?