Spring - No EntityManager with actual transaction available for current thread - cannot reliably process "persist" call

Spring - No EntityManager with actual transaction available for current thread - cannot reliably process 'persist' call

So, you're working on your Spring MVC web application, and you encounter this error when trying to save an entity model to the database using the "persist" method. You've searched the internet but can't find any relevant solutions. Don't worry, we've got you covered! In this blog post, we'll address the common issues and provide easy solutions to fix this error.

Understanding the Problem

This error usually occurs when there is no EntityManager with an actual transaction available for the current thread. It means that something is going wrong with the EntityManagerFactory bean, which is responsible for managing the EntityManager instances in your application.

Diagnosis: Looking into the Code

Let's take a look at the code provided to identify any potential issues.

dispatcher-servlet.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xsi:schemaLocation="
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-4.0.xsd
        ...
        "
>

    <!-- Component scanning and bean definitions -->

    <!-- EntityManagerFactory bean definition -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        ...
    </bean>

    <!-- Other bean definitions -->

    <mvc:annotation-driven />

    <!-- View resolver and resource mappings -->

</beans>

RegisterController.java

@Controller
public class RegisterController {

    @PersistenceContext
    EntityManager entityManager;

    ...

    @RequestMapping(value = "/addUser", method = RequestMethod.POST)
    public String register(@ModelAttribute("person") @Valid @Validated Person person, BindingResult result) {
        if(result.hasErrors()) {
            return "register";
        } else {
            entityManager.persist(person);
            return "index";
        }
    }
}

From the code, we can see that:

• We have defined the entityManagerFactory bean in the dispatcher-servlet.xml file.

• In the RegisterController class, we have injected the EntityManager using @PersistenceContext annotation.

Solutions: Fixing the Error

Based on our diagnosis, there are a few potential solutions to fix this error.

Solution 1: Configure Transaction Management

To ensure that an actual transaction is available for the current thread, we need to configure transaction management in our Spring application.

1. Add the following bean definition in dispatcher-servlet.xml:

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

1. Add the @Transactional annotation to the register method in RegisterController.java:

@Transactional
@RequestMapping(value = "/addUser", method = RequestMethod.POST)
public String register(@ModelAttribute("person") @Valid @Validated Person person, BindingResult result) {
    ...
}

Solution 2: Verify EntityManagerFactory Configuration

It's possible that the configuration for the entityManagerFactory bean is incorrect. Double-check the following:

1. Verify that the persistenceXmlLocation property in the entityManagerFactory bean refers to a valid location of your persistence.xml file.

2. Ensure that the dataSource bean is correctly configured with the appropriate properties for your database connection.

Solution 3: Check Dependencies and Versions

Make sure that you have the required dependencies and compatible versions for Spring MVC, Spring Data JPA, and Hibernate in your project.

1. Check your project's dependencies and ensure that you have the necessary JAR files.

2. Verify that the versions of Spring MVC, Spring Data JPA, and Hibernate are compatible.

Put Your Solutions to Action

After applying one or more of these solutions, recompile and run your application to see if the error is resolved. If you encounter any other issues or have further questions, feel free to leave a comment below.

Conclusion

In this blog post, we discussed the common issue of getting the "No EntityManager with actual transaction available for current thread" error when trying to persist an entity model in a Spring MVC web application. We explored possible causes and provided easy-to-implement solutions to fix the error. Now it's your turn! Apply these solutions to your code and test it out. Share your experience, questions, or any other insights in the comments section.

Happy coding! 👨‍💻💥