Spring core. Default @Bean destroy method

Question

I have my own bean:

@Bean
public MyBean myBean(){...

following spring documentation to release its own resources I should specify destroyMethod. I've not found any default destroy methods called by spring in case if destroyMethod is not specified directly.

I used

@Bean(destroyMethod = "close")
public MyBean myBean(){...

but think about possibility to do not specify destroy method directly if it has value by default.

---

Does spring try something by default like destroy, close, release? If spring tries some methods by default to release resources - which ones?

Answer 1

As documented in Bean.destroyMethod:

As a convenience to the user, the container will attempt to infer a destroy method against an object returned from the @Bean method. For example, given an @Bean method returning an Apache Commons DBCP BasicDataSource, the container will notice the close() method available on that object and automatically register it as the destroyMethod. This 'destroy method inference' is currently limited to detecting only public, no-arg methods named 'close' or 'shutdown'.

In other words, if you don't specify destroyMethod, but the bean has a public close() or shutdown() method, it will be automatically used as the destroy-method.

To disable this inference, use @Bean(destroyMethod = "").

Answer 2

You can implement a method which will be executed before destroying and annotate it with @PreDestroy

@PreDestroy
public void methodName() {
    //Your code..
}

Answer 3

The org.springframework.beans.factory.DisposableBean interface specifies a single method −

void destroy() throws Exception;

Simply implement it −

public class ExampleBean implements DisposableBean {
   public void destroy() {
      // do some destruction work
   }
}

for XML-based configuration

<bean id = "exampleBean" class = "examples.ExampleBean" destroy-method = "destroy"/>

and in the bean

public class ExampleBean {
   public void destroy() {
      // do some destruction work
   }
}

or annotate with @PreDestroy

Answer 4

You can extend DisposableBeanAdapter class. One of the methods it provides is the destroy method being called by Spring. This way you don't have to provide any implementation while it is required when you're using DisposableBean interface.