Spring @Component Annotation

The @Component Annotation Indicates that an annotated class is a "component". Such classes are considered as candidates for auto-detection when using annotation-based configuration and classpath scanning. 
The @Component is a generic stereotype for any Spring-managed component. @Repository, @Service, and @Controller are specializations of @Component for more specific use cases, for example, in the persistence, service, and presentation layers, respectively.
Spring @Component Annotation
 See the following example using component annotation:

package com.dineshonjava.sdnext.componentstreatypeannotation.tutorail;

import javax.annotation.Resource;

import org.springframework.stereotype.Component;

public class Triangle
 private Point pointA;
 private Point pointB;
 private Point pointC;
  * Using @Resource annotation for wiring with bean dependency
  * @param pointA the pointA to set
 public void setPointA(Point pointA) {
  this.pointA = pointA;

  * Using @Resource annotation for wiring with bean dependency
  * @param pointB the pointB to set
 public void setPointB(Point pointB) {
  this.pointB = pointB;

  * Using @Resource annotation for wiring with bean dependency
  * @param pointC the pointC to set
 public void setPointC(Point pointC) {
  this.pointC = pointC;

 public void draw()
System.out.println("Drawing Triangle");
System.out.println("PointA is ("+pointA.getX()+", "+pointA.getY()+")");
System.out.println("PointB is ("+pointB.getX()+", "+pointB.getY()+")");
System.out.println("PointC is ("+pointC.getX()+", "+pointC.getY()+")");

Here we are using @Component annotation with the Triangle class which auto detect as bean in Spring IoC Container.

package com.dineshonjava.sdnext.componentstreatypeannotation.tutorail;

public class Point
 private int x;
 private int y;
  * @return the x
 public int getX() {
  return x;
  * @param x the x to set
 public void setX(int x) {
  this.x = x;
  * @return the y
 public int getY() {
  return y;
  * @param y the y to set
 public void setY(int y) {
  this.y = y;

package com.dineshonjava.sdnext.componentstreatypeannotation.tutorail;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

 * @author Dinesh
public class DrawingApp 
  * @param args
 public static void main(String[] args) 
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
Triangle triangle= (Triangle) context.getBean("triangle");

<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:security="http://www.springframework.org/schema/security" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/beans">
<bean class="com.dineshonjava.sdnext.componentstreatypeannotation.tutorail.Point" id="pointA">
<property name="x" value="0"></property>
<property name="y" value="0"></property>
<bean class="com.dineshonjava.sdnext.componentstreatypeannotation.tutorail.Point" id="pointB">
<property name="x" value="-20"></property>
<property name="y" value="0"></property>

<bean class="com.dineshonjava.sdnext.componentstreatypeannotation.tutorail.Point" id="pointC">
<property name="x" value="20"></property>
<property name="y" value="0"></property>
<context:component-scan base-package="com.dineshonjava.sdnext.componentstreatypeannotation.tutorail">

Here <context:component-scan/> scan the all classes in the base package given as "com.dineshonjava.sdnext.componentstreatypeannotation.tutorail" which are annotated with the @Component annotation or its specific annotations like @Component, @Repository, @Service & @Controller etc then these classes detect as bean of Spring IoC Container.

If every thing is OK then run that application we will get the following output.
Jul 14, 2012 8:54:13 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@ab50cd: startup date [Sat Jul 14 20:54:13 IST 2012]; root of context hierarchy
Jul 14, 2012 8:54:13 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [spring.xml]
Jul 14, 2012 8:54:14 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@1198891: defining beans [pointA,pointB,pointC,center,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,circle,triangle,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; root of factory hierarchy
Drawing Triangle
PointA is (0, 0)
PointB is (-20, 0)
PointC is (20, 0)

Spring Related Topics you may like
  1. Spring Interview Questions and Answers
  2. Spring AOP Interview Questions and Answers
  3. Spring MVC Interview Questions
  4. Spring Security Interview Questions and Answers
  5. Spring REST Interview Questions and Answers
  6. Spring Boot Interview Questions and Answers
  7. Spring Boot Microservices Interview Questions and Answers
  8. Dependency Injection (DI) in Spring
  9. Spring IoC Container
  10. What is Bean Factory in Spring
  11. ApplicationContext in Spring
  12. Bean Autowiring in Spring
  13. Spring Bean Scopes
  14. Create Custom Bean Scope in Spring Example
  15. Using ApplicationContextAware in Spring
  16. Spring Bean Life Cycle and Callbacks
  17. BeanPostProcessor in Spring
  18. BeanFactoryPostProcessor in Spring
  19. Annotations in Spring and Based Configuration
  20. Spring JSR-250 Annotations
  21. JSR 330 Annotations in Spring
  22. Spring @Component, @Repository, @Service and @Controller Stereotype Annotations
  23. Method injection with Spring using Lookup method property
  24. Spring AOP-Introduction to Aspect Oriented Programming
  25. @Aspect Annotation in Spring
  26. Spring AOP AspectJ @Before Annotation Advice Example
  27. Spring AOP Before Advice Example using XML Config
  28. Spring AOP AspectJ @After Annotation Advice Example
  29. Spring AOP After Advice Example using XML Config
  30. Spring AOP AspectJ @AfterReturning Annotation Advice Example
  31. Spring AOP After-Returning Advice Example using XML Config
  32. Spring AOP AspectJ @AfterThrowing Annotation Advice Example
  33. Spring AOP After Throwing Advice Example using XML Config
  34. Spring AOP AspectJ @Around Annotation Advice Example
  35. Spring AOP Around Advice Example using XML Config
  36. Spring AOP Proxies in Spring
  37. Spring AOP Transaction Management in Hibernate
  38. Spring Transaction Management
  39. Spring Declarative Transaction Management Example
  40. Spring AOP-Ordering of Aspects with Example
  41. Spring Security Java Based Configuration with Example
  42. Spring Security XML Namespace Configuration Example