Spring @ComponentScan tutorial

last modified October 18, 2023

Spring @ComponentScan tutorial shows how to enable component scanning in a Spring application. Component scanning enables auto-detection of beans by Spring container.

Spring is a popular Java application framework for creating enterprise applications.

Spring @ComponentScan

@ComponentScan annotation enables component scanning in Spring. Java classes that are decorated with stereotypes such as @Component, @Configuration, @Service are auto-detected by Spring. The @ComponentScan's basePackages attribute specifies which packages should be scanned for decorated beans.

The @ComponentScan annotation is an alternative to <context:component-scan> XML tag.

Spring @ComponentScan example

The application enables component scanning with @ComponentScan. We have one service bean that returns the current time.

│   ├───java
│   │   └───com
│   │       └───zetcode
│   │           │   Application.java
│   │           └───service
│   │                   TimeService.java
│   └───resources
│           logback.xml

This is the project structure.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"










In the pom.xml file, we have basic Spring dependencies spring-core, spring-context, and logging logback-classic dependency.

The exec-maven-plugin is used for executing Spring application from the Maven on the command line.

<?xml version="1.0" encoding="UTF-8"?>
    <logger name="org.springframework" level="ERROR"/>
    <logger name="com.zetcode" level="INFO"/>

    <appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
            <Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n

        <level value="INFO" />
        <appender-ref ref="consoleAppender" />

The logback.xml is a configuration file for the Logback logging library.

package com.zetcode.service;

import org.springframework.stereotype.Service;

import java.time.LocalTime;

public class TimeService {

    public LocalTime getTime() {

        var now = LocalTime.now();

        return now;

The TimeService class is annotated with the @Service annotation. It is registered by Spring as a managed bean with the help of component scanning.

package com.zetcode;

import com.zetcode.service.TimeService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@ComponentScan(basePackages = "com.zetcode")
public class Application {

    private static final Logger logger = LoggerFactory.getLogger(Application.class);

    public static void main(String[] args) {

        var ctx = new AnnotationConfigApplicationContext(Application.class);

        var timeService = (TimeService) ctx.getBean("timeService");
        logger.info("The time is {}", timeService.getTime());


The application is annotated with @ComponentScan. The basePackages option tells Spring to look for components in the com/zetcode package and its subpackages.

var ctx = new AnnotationConfigApplicationContext(Application.class);

AnnotationConfigApplicationContext is a Spring standalone application context. It accepts the annotated Application as an input; thus the scanning is enabled.

var timeService = (TimeService) ctx.getBean("timeService");
logger.info("The time is {}", timeService.getTime());

We get the registered service bean and call its method.

$ mvn -q exec:java
10:57:01.912 INFO  com.zetcode.Application - The time is 10:57:01.912235800

We run the application.

In this article we have enabled component scanning with @ComponentScan.


My name is Jan Bodnar and I am a passionate programmer with many years of programming experience. I have been writing programming articles since 2007. So far, I have written over 1400 articles and 8 e-books. I have over eight years of experience in teaching programming.

List all Spring tutorials.