- Why do we use beans?
- What is @configuration in spring?
- What is a bean in Java Spring?
- What is spring boot pojo?
- How do you control a bean life cycle in spring?
- What is Spring POJO?
- What is bean annotation in spring?
- How many ways can you make a bean in spring?
- Can we replace @service with @component?
- Are all spring beans singletons?
- What is the purpose of bean scope?
- What is difference between Bean and object?
- Is @component a bean in spring?
- What does Bean mean in Java?
- What is spring bean life cycle?
- What is scope of bean in spring?
- Is Spring beans are thread safe?
- What is the purpose of @autowired in spring?
Why do we use beans?
Why use JavaBean.
According to Java white paper, it is a reusable software component.
A bean encapsulates many objects into one object so that we can access this object from multiple places.
Moreover, it provides easy maintenance..
What is @configuration in spring?
@Configuration annotation indicates that a class declares one or more @Bean methods and may be processed by the Spring container to generate bean definitions and service requests for those beans at runtime. … This is called Spring Java Config feature (using @Configuration annotation).
What is a bean in Java Spring?
In Spring, the objects that form the backbone of your application and that are managed by the Spring IoC container are called beans. A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. Otherwise, a bean is simply one of many objects in your application.
What is spring boot pojo?
Answer: POJO stands for “Plain Old Java Object” — it’s a pure data structure that has fields with getters and possibly setters, and may override some methods from Object (e.g. equals) or some other interface like Serializable, but does not have behavior of its own.
How do you control a bean life cycle in spring?
Spring framework provides following 4 ways for controlling life cycle events of a bean:InitializingBean and DisposableBean callback interfaces.*Aware interfaces for specific behavior.Custom init() and destroy() methods in bean configuration file.@PostConstruct and @PreDestroy annotations.
What is Spring POJO?
POJO stands for Plain Old Java Object. It is an ordinary Java object, not bound by any special restriction other than those forced by the Java Language Specification and not requiring any classpath. POJOs are used for increasing the readability and re-usability of a program.
What is bean annotation in spring?
Spring @Bean Annotation is applied on a method to specify that it returns a bean to be managed by Spring context. Spring Bean annotation is usually declared in Configuration classes methods. In this case, bean methods may reference other @Bean methods in the same class by calling them directly.
How many ways can you make a bean in spring?
There are three different ways in which you can define a Spring bean: annotating your class with the stereotype @Component annotation (or its derivatives) writing a bean factory method annotated with the @Bean annotation in a custom Java configuration class. declaring a bean definition in an XML configuration file.
Can we replace @service with @component?
According to documentaion @Repository , @Service , @Controller are all synonyms. They all just specializations of @Component annotation. So, generally, they can be used one istead of other.
Are all spring beans singletons?
Spring’s default scope is singleton. … Here is how the Spring documentation defines singleton scope: Only one shared instance of a singleton bean is managed, and all requests for beans with an id or ids matching that bean definition result in that one specific bean instance being returned by the Spring container.
What is the purpose of bean scope?
Only valid in the context of a web-aware Spring ApplicationContext. In Spring, bean scope is used to decide which type of bean instance should be returned from Spring container back to the caller. 5 types of bean scopes are supported : Singleton : It returns a single bean instance per Spring IoC container.
What is difference between Bean and object?
The only difference between both the classes is Java make java beans objects serialized so that the state of a bean class could be preserved in case required.So due to this a Java Bean class must either implements Serializable or Externalizable interface.
Is @component a bean in spring?
@Component is a class level annotation whereas @Bean is a method level annotation and name of the method serves as the bean name.
What does Bean mean in Java?
JavaBeansIn computing based on the Java Platform, JavaBeans are classes that encapsulate many objects into a single object (the bean). They are serializable, have a zero-argument constructor, and allow access to properties using getter and setter methods.
What is spring bean life cycle?
A “Spring bean” is just a Spring managed instantiation of a Java class. The Spring IoC container is responsible for instantiating, initializing, and wiring beans. The container also manages the life cycle of beans. Spring provides several ways through which you can tap into the bean lifecycle.
What is scope of bean in spring?
Scopes a single bean definition to a single object instance per Spring IoC container. … Scopes a single bean definition to the lifecycle of a single HTTP request; that is each and every HTTP request will have its own instance of a bean created off the back of a single bean definition.
Is Spring beans are thread safe?
Spring singleton beans are NOT thread-safe just because Spring instantiates them. Sorry. Spring just manage the life cycle of singleton bean and maintains single instance of object. Thread safety has nothing to do with it.
What is the purpose of @autowired in spring?
Autowiring feature of spring framework enables you to inject the object dependency implicitly. It internally uses setter or constructor injection. Autowiring can’t be used to inject primitive and string values.