Annotate Required Field Release For Free

@Component is a class-level annotation. It is used to denote a class as a Component. We can use @Component across the application to mark the beans as Spring's managed components.

2 Answers. As you can see, the only way to declare your Service final is by using the constructor injection, which replaces the @Required annotation because it forces the user of your class to instantiate it with the required services. The user does not have to be Spring, it could be a simple unit test as well.

The @Required annotation applies to bean property setter methods and it indicates that the affected bean property must be populated in XML configuration file at configuration time. Otherwise, the container throws a BeanInitializationException exception. Following is an example to show the use of @Required annotation.

Annotations are used to provide supplemental information about a program. Annotations start with '@'. Annotations do not change the action of a compiled program. Annotations help to associate metadata (information) to the program elements i.e. instance variables, constructors, methods, classes, etc.

We can enable @Required annotation in two ways in Spring XML configuration: Either by registering RequiredAnnotationBeanPostProcessor in the bean definition. Or can be implicitly registered by including the <context:annotation-config/> tag in an XML-based Spring configuration.

If you use @Autowired annotation on a field, that field will be autowired with bean having matching data type. @Required checks if a particular property has been set or not. If a field has been annotated with @Required annotation and that field is not set, you will get org.

Use @Field to define a structured data type's field name for an object mapped to NoSql data. Table 2-24 describes this annotation's elements. (Optional) The data type's name of the field. The @Field annotation is a generic form of the @Column annotation, which is not specific to relational databases.