How does the system handle a call to a transactional method from a non-transactional method?

If a non-transactional method calls a transactional method, the behavior depends on the framework used and the transaction settings. In most cases, when a transactional method is called from a non-transactional one, the system will create a new transaction for that method. For example, in the Spring Framework, if the outer method does not have a transaction, but the called method is annotated with @Transactional, a new transaction will be created for the called method.

Example (Spring):

public class Service {
    public void nonTransactionalMethod() {
        transactionalMethod(); // A new transaction will be created here
    }

    @Transactional
    public void transactionalMethod() {
        // code within a transaction
    }
}

It is important to note that if a transactional method is called directly within the same class, Spring's proxy may not work, and a transaction may not be created. For proper transaction handling, the call should go through a proxy (for example, through another bean).