How to manually trigger spring validation?

Question

The annotated spring validation on fields of a POJO works when it is created from json request body. However, when I create the same object manually (using setters) and want

Answer 1

Spring provides full support for the JSR-303 Bean Validation API. This includes convenient support for bootstrapping a JSR-303 implementation as a Spring bean. This allows a javax.validation.Validator to be injected wherever validation is needed in your application.

Use the LocalValidatorFactoryBean to configure a default JSR-303 Validator as a Spring bean:

   <bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" />

The basic configuration above will trigger JSR-303 to initialize using its default bootstrap mechanism. A JSR-303 provider, such as Hibernate Validator, is expected to be present in the classpath and will be detected automatically.

5.7.2.1 Injecting a Validator

LocalValidatorFactoryBean implements both javax.validation.Validator and org.springframework.validation.Validator. You may inject a reference to one of these two interfaces into beans that need to invoke validation logic.

Inject a reference to javax.validation.Validator if you prefer to work with the JSR-303 API directly:

// JSR-303 Validator
import javax.validation.Validator;

@Service
public class MyService {

    @Autowired
    private Validator validator;

}

Inject a reference to org.springframework.validation.Validator if your bean requires the Spring Validation API:

// Spring Validator
import org.springframework.validation.Validator;

@Service
public class MyService {

    @Autowired
    private Validator validator;

}

Here is a well exaplained example Using JSR 303 with "classic" Spring Validators (enter the SpringValidatorAdapter)

This link is very helpful. Wrapping javax.validation.Validator in org.springframework.validation.beanvalidation.SpringValidatorAdapter helped deal with errors consistently. Can you add this as an answer so that I can accept it

and Spring doc here