What is @transactional annotation in Java?

What does @transactional annotation do?


The @Transactional annotation is the metadata that specifies the semantics of the transactions on a method. We have two ways to rollback a transaction: declarative and programmatic. … The default rollback behavior in the declarative approach will rollback on runtime exceptions.

What is transactional annotation Java?

Transactional annotation provides the application the ability to declaratively control transaction boundaries on CDI managed beans, as well as classes defined as managed beans by the Java EE specification, at both the class and method level where method level annotations override those at the class level.

When should we use @transactional annotation?

@Transactional should be used on specific methods where it is actually needed, not on the entire class. This makes it easier to see which methods are meant to be executed as one transaction, and which ones are not. You don’t need @Transactional for database operations that only read from the database.

What is the function of the @transactional annotation at class level?

Annotation Type Transactional. Describes a transaction attribute on an individual method or on a class. When this annotation is declared at the class level, it applies as a default to all methods of the declaring class and its subclasses.

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What is the use of @repository annotation?

The @Repository annotation is a marker for any class that fulfils the role or stereotype of a repository (also known as Data Access Object or DAO). Among the uses of this marker is the automatic translation of exceptions, as described in Exception Translation.

Is @transactional mandatory?

REQUIRED is the default setting of a @Transactional annotation. … Each method annotated with REQUIRED demarcates a logical transaction and these logical transactions participate in the same physical transaction.

Where @autowired can be used?

The @Autowired annotation can be used to autowire bean on the setter method just like @Required annotation, constructor, a property or methods with arbitrary names and/or multiple arguments.

What is @transactional in JPA?

@Transactional annotation is used when you want the certain method/class(=all methods inside) to be executed in a transaction.

Why do we use @transactional annotation in spring?

So when you annotate a method with @Transactional , Spring dynamically creates a proxy that implements the same interface(s) as the class you’re annotating. And when clients make calls into your object, the calls are intercepted and the behaviors injected via the proxy mechanism.

Can we use @transactional in controller?

The controller can be made @Transactional , but indeed it’s a common recommendation to only make the service layer transactional (the persistence layer should not be transactional either).

Can we use @transactional with class?

@Transactional on a class applies to each method on the service. It is a shortcut. Typically, you can set @Transactional(readOnly = true) on a service class, if you know that all methods will access the repository layer. You can then override the behavior with @Transactional on methods performing changes in your model.

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What does @transactional readOnly true do?

If we use @Transactional(readOnly = true) to a method which is performing create or update operation then we will not have newly created or updated record into the database but we will have the response data.

What is the @bean annotation?

@Bean is a method-level annotation and a direct analog of the XML <bean/> element. The annotation supports most of the attributes offered by <bean/> , such as: init-method , destroy-method , autowiring , lazy-init , dependency-check , depends-on and scope .