Which annotation is equivalent to @SpringBootApplication?
The @SpringBootApplication annotation is equivalent to using @Configuration , @EnableAutoConfiguration and @ComponentScan with their default attributes: [] If specific packages are not defined, scanning will occur from the package of the class that declares this annotation.
What is the use of @EnableAutoConfiguration annotation?
The @EnableAutoConfiguration annotation enables Spring Boot to auto-configure the application context. Therefore, it automatically creates and registers beans based on both the included jar files in the classpath and the beans defined by us.
What is the use of annotations in spring boot?
Spring Boot Annotations is a form of metadata that provides data about a program that is not a part of the program itself. They do not have any direct effect on the operation of the code they annotate. Spring Boot Annotations do not use XML and instead use the convention over configuration principle.
Related Question What is the use of @SpringBootApplication?
Which of the following features are enabled using @SpringBootApplication?
A single @SpringBootApplication annotation can be used to enable those three features, that is:
What is the use of DataSourceAutoConfiguration?
During application startup, the DataSourceAutoConfiguration checks for DataSource. class (or EmbeddedDatabaseType. class) on the classpath and a few other things before configuring a DataSource bean for us.
What is @ServletComponentScan?
Annotation Type ServletComponentScan
Enables scanning for Servlet components ( filters , servlets , and listeners ). Scanning is only performed when using an embedded web server. Typically, one of value , basePackages , or basePackageClasses should be specified to control the packages to be scanned for components.
What is the @controller annotation used for?
The basic purpose of the @Controller annotation is to act as a stereotype for the annotated class, indicating its role. The dispatcher will scan such annotated classes for mapped methods, detecting @RequestMapping annotations (see the next section).
What is @component annotation in spring?
@Component is an annotation that allows Spring to automatically detect our custom beans. In other words, without having to write any explicit code, Spring will: Scan our application for classes annotated with @Component. Instantiate them and inject any specified dependencies into them. Inject them wherever needed.
Is spring boot a server?
Each Spring Boot web application includes an embedded web server. This feature leads to a number of how-to questions, including how to change the embedded server and how to configure the embedded server.
Which server does spring boot use?
By default, Spring Boot uses Tomcat 7. If you want to use Tomcat 8, just say so! You need only override the Maven build's tomcat. version property and this will trigger the resolution of later builds of Apache Tomcat.
What is the use of Autowired annotation in spring boot?
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.
What is IOC and DI in spring?
IOC is technique where you let someone else to create the object for you. And the someone else in case of spring is IOC container. Dependency Injection is a technique where one object supplies the dependency of another object.
What is Autowired?
Autowiring happens by placing an instance of one bean into the desired field in an instance of another bean. Both classes should be beans, i.e. they should be defined to live in the application context.
What is the use of IoC container?
IoC Container (a.k.a. DI Container) is a framework for implementing automatic dependency injection. It manages object creation and it's life-time, and also injects dependencies to the class.
How do I connect two spring boot databases?
What is Springboot autoconfiguration?
Simply put, the Spring Boot autoconfiguration represents a way to automatically configure a Spring application based on the dependencies that are present on the classpath. This can make development faster and easier by eliminating the need for defining certain beans that are included in the auto-configuration classes.
What is Hikari?
Hikari is a JDBC DataSource implementation that provides a connection pooling mechanism. Compared to other implementations, it promises to be lightweight and better performing. This quick tutorial shows how we can configure a Spring Boot 2 or Spring Boot 1 application to use the Hikari DataSource.
What is ServletContextListener?
ServletContextListener is an interface that gets notified about ServletContext lifecycle changes. It offers two methods. contextInitialized - Is triggered when the web application is starting the initialization. This will be invoked before any of the filters and servlets are initialized.
What is difference between @SpringBootApplication and EnableAutoConfiguration?
@SpringBootApplication is a newer version of @EnableAutoConfiguration which was introduced in Spring Boot 1.2. @ComponentScan enables component scanning so that web controller classes and other components that you create will be automatically discovered and registered as beans in spring's application context.
What is @service and @repository?
The repository is where the data is stored. The service is what manipulates the data. In a real-world situation comparison, if your money is stored in a vault in a bank, the vault is the repository. The teller that deposits, withdraws, etc is the service.
What is Controller Java?
A controller basically controls the flow of the data. It controls the data flow into model object and updates the view whenever data changes.
What is get mapping?
The @GetMapping annotation is a specialized version of @RequestMapping annotation that acts as a shortcut for @RequestMapping(method = RequestMethod. GET) . The @GetMapping annotated methods in the @Controller annotated classes handle the HTTP GET requests matched with given URI expression.
What is annotation used for?
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.
Is @component a bean?
@Component is a class level annotation whereas @Bean is a method level annotation and name of the method serves as the bean name.
What is Classpath scanning in Spring?
A Classpath scanning basically means, detecting the classes that need to be managed by the Spring under a specified package. You need to make use of the spring @ComponentScan annotation with the @Configuration for classpath scanning.
Why entity is used in hibernate?
hibernate package tree is Hibernate specific. The @Entity annotation is used to mark this class as an Entity bean. So the class should atleast have a package scope no-argument constructor. The @Table annotation is used to specify the table to persist the data.
What is a Microservices in Java?
Java microservices are a set of software applications written in the Java programming language (and typically leverage the vast ecosystem of Java tools and frameworks), designed for limited scope that work with each other to form a bigger solution.
What is the advantage of spring boot?
Advantages of SpringBoot:
DevTools to autorestart server on code/config updates. Embedded Tomcat/Jetty/Undertow support. Easier customization of application properties. Easy management of profile specific properties.
What is loader path?
loader. path : a comma-separated list of directories (containing file resources and/or nested archives in *. zip or archives) or archives to append to the classpath. BOOT-INF/classes,BOOT-INF/lib in the application archive are always used. loader.
What is Reactor Netty?
Reactor Netty is an asynchronous event-driven network application framework. It provides non-blocking and backpressure-ready TCP, HTTP, and UDP clients and servers. Spring WebFlux is a part of the Spring framework and provides reactive programming support for web applications.
What is a Spring cloud?
Spring Cloud is a framework for building robust cloud applications. Applications that run with microservices architecture aim to simplify development, deployment, and maintenance. The decomposed nature of the application allows developers to focus on one problem at a time.
Does Spring boot need Apache?
Before you get started, it's important to keep in mind that a Spring Boot app is just a web app that's packaged with an embedded Apache Tomcat Application Server.
Does Spring use Tomcat?
By default, Spring Boot uses Tomcat 7. If you want to use Tomcat 8, just say so! You need only override the Maven build's tomcat. version property and this will trigger the resolution of later builds of Apache Tomcat.
Is Java Spring a Web server?
One of the most popular uses is as a web server, using one of the many supported embedded servlet containers and template engines. However, Spring Boot has a number of uses that do not require a web server: console applications, job scheduling, batch or stream processing, serverless applications, and more.
What is the use of @service in spring boot?
Spring @Service annotation is used with classes that provide some business functionalities. Spring context will autodetect these classes when annotation-based configuration and classpath scanning is used.
What is spring bean?
By definition, a Spring bean is an object that form the backbone of your application and that is managed by the Spring IoC container. 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 bean scope?
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. Scopes a single bean definition to the lifecycle of a global HTTP Session .
What is Java Di?
Dependency injection (DI) is the concept in which objects get other required objects from outside. The general concept behind dependency injection is called Inversion of Control. A Java class has a dependency on another class, if it uses an instance of this class. We call this a class dependency.
Which is better constructor or setter injection?
Overriding: Setter injection overrides the constructor injection. If we use both constructor and setter injection, IOC container will use the setter injection. It doesn't create a new bean instance always like constructor. So setter injection is flexible than constructor injection.