Yes, you can configure two beans with the same id, in this case the bean which is mentioned in the last will be considered. <bean name="bean"/> Here when you call the bean in your code with the bean id as “bean” then always the second instance will be returned.

Likewise, people ask, can a bean have multiple names?

Bean Names

Also note that name accepts an array of Strings, allowing for multiple names (i.e. a primary bean name plus one or more aliases) for a single bean.

Also, what is a bean id? Every bean has one or more ids (also called identifiers, or names; these terms refer to the same thing). These ids must be unique within the container the bean is hosted in. When using XML-based configuration metadata, you use the 'id' or 'name' attributes to specify the bean identifier(s).

Also Know, can we create multiple Singleton beans of same class in spring?

It will throw an error at runtime, as you can not define two Sspring beans of the same class with Singleton Scope in XML. (Very rare) The reference check will return true, as the container maintains one object. Both bean definitions will return the same object, so the memory location would be the same.

Which scope creates a new bean instance each time when requested?

2 The prototype scope. The non-singleton, prototype scope of bean deployment results in the creation of a new bean instance every time a request for that specific bean is made. That is, the bean is injected into another bean or you request it through a getBean() method call on the container.

Related Question Answers

What is the difference between @component and @bean?

@Component is a class level annotation whereas @Bean is a method level annotation and name of the method serves as the bean name. @Component need not to be used with the @Configuration annotation where as @Bean annotation has to be used within the class which is annotated with @Configuration.

What is a bean in 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 does Bean annotation do?

@Bean annotation indicates that the annotated method produces a bean to be managed by the Spring container. It is a direct analog of the <bean/> XML tag. @Bean supports most of the attributes offered by <bean/> , such as: init-method , destroy-method , autowiring , lazy-init , dependency-check , depends-on , scope .

Why bean class is used in Java?

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 the default bean name in spring?

Bean Names

The default bean name is @Bean annotated method name.

What is the use of @configuration in spring?

Spring @Configuration annotation is part of the spring core framework. Spring Configuration annotation indicates that the class has @Bean definition methods. So Spring container can process the class and generate Spring Beans to be used in the application.

Which configuration can be used for dependency injection?

Constructor injection — good, reliable and immutable, inject via one of the constructors. Possible to configure in: XML, XML+Annotations, Java, Java + Annotations. Setter injection — more flexible, mutable objects, injection via setters. Possible to configure in: XML, XML+Annotations, Java, Java + Annotations.

What is the use of alias in spring?

Alias is used to give another name to spring.

Can we have 2 beans with same ID in spring?

It valid as long as you are defining two bean definitions with same id of same bean on two different spring configuration files. The later one or the last one bean definition will be override by the first one(s).

Is Autowired thread safe?

Is Spring singleton thread safe? The short answer is: no, it isn't. If you don't use @Lazy, the framework creates a singleton bean at the application startup and makes sure that the same instance is autowired and reused in all other dependent beans. As long the container lives, the singleton beans live as well.

Is Singleton bean thread safe?

Singleton Beans is thread safe or not depends on how the class whose scope is singleton is written. Each calling thread will have its own execution and does not interfere with another thread's execution unless there is some code in the singleton scoped class which is shared by all calling threads.

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.

Are spring boot beans singletons?

Spring Singleton bean

Singleton beans are created when the Spring container is created and are destroyed when the container is destroyed. Singleton beans are shared; only one instance of a singleton bean is created per Spring container. Singleton scope is the default scope for a Spring bean.

Is Autowired a singleton?

Autowiring. When you autowire a bean, you ask Spring for an instance of the bean from the application context. If you autowire a singleton bean, Spring looks for an existing instance inside the application context and provides it to you.

Are beans singletons?

When a bean is a singleton, only one shared instance of the bean will be managed, and all requests for beans with an id or id s matching that bean definition will result in that one specific bean instance being returned by the Spring container.

Why spring bean scope is singleton by default?

singleton is default bean scope in spring container. It tells the container to create and manage only one instance of bean class, per container. This single instance is stored in a cache of such singleton beans, and all subsequent requests and references for that named bean return the cached instance.

Is Spring prototype bean thread safe?

Are Spring Beans Thread Safe? No. Spring has different bean scopes (e.g. Prototype, Singleton, etc.) For example a "prototype" scoped bean will be created each time this bean is "injected", whereas a "singleton" scoped bean will be created once and shared within the application context.

What is a bean life cycle?

Similarly, the bean life cycle refers to when & how the bean is instantiated, what action it performs until it lives, and when & how it is destroyed. In this article, we will discuss the life cycle of the bean. Bean life cycle is managed by the spring container.

What is a bean method?

Spring @Bean annotation tells that a method produces a bean to be managed by the Spring container. It is a method-level annotation. During Java configuration ( @Configuration ), the method is executed and its return value is registered as a bean within a BeanFactory .

How do you call a bean method 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 do you create an annotation in a spring bean?

Creating beans using component scanning can be done in two steps.

1. 1.1. Annotate beans with respective component annotations. We shall use use one of following four annotations as appropriate. @Component.
2. 1.2. Include bean packages in @ComponentScan annotation. AppConfig.java.
3. 1.3. Demo. package com.howtodoinjava.spring;

How many ways can you create bean in spring boot?

There are three different ways in which you can define a Spring bean:

1. annotating your class with the stereotype @Component annotation (or its derivatives)
2. writing a bean factory method annotated with the @Bean annotation in a custom Java configuration class.
3. declaring a bean definition in an XML configuration file.

Which scope creates a new bean for each request?

The prototype scope

If the scope is set to prototype, the Spring IoC container creates a new bean instance of the object every time a request for that specific bean is made. As a rule, use the prototype scope for all state-full beans and the singleton scope for stateless beans.

Which of the following is not the scope of beans in spring?

Explanation: In Spring 1. x, singleton and prototype are the only two valid bean scopes, and they are specified by the singleton attribute (i.e., singleton=”true” or singleton=”false”), not the scope attribute.

How do you use the ref keyword in beans?

Spring bean reference example

1. Bean in different XML files. If you are referring to a bean in different XML file, you can reference it with a ' ref ' tag, ' bean ' attribute. <ref bean="someBean"/>
2. Bean in same XML file. If you are referring to a bean in same XML file, you can reference it with ' ref ' tag, ' local ' attribute. <ref local="someBean"/>

What is difference between Singleton and prototype bean?

Singleton: Only one instance will be created for a single bean definition per Spring IoC container and the same object will be shared for each request made for that bean. Prototype: A new instance will be created for a single bean definition every time a request is made for that bean.

What is stateless bean in spring?

From spring perspective. stateless beans: beans that are singleton and are initialized only once. The only state they have is a shared state. These beans are created while the ApplicationContext is being initialized. The SAME bean instance will be returned/injected during the lifetime of this ApplicationContext .

What is bean Autowiring?

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. It works with reference only.

What is the scope of Bean in portlet context?

session - Scopes a single bean definition to the lifecycle of an HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext. global session - Scopes a single bean definition to the lifecycle of a global HTTP Session. Typically only valid when used in a portlet context.

Which is the way to provide configuration metadata to spring?

Q 18 - Which is the way to provide configuration metadata to spring? A - XML Based configuration file.

Which one is the default scope of the beans?

Singleton