problem with spring boot component scanning

Question

I am writing spring boot application which has two entity classes Teacher and Department. I am using JPA and H2 in-memory database. When i run the application tables are not creating in h2 database. I have specified package to scan using @componentScan annotation but i thinks spring is not finding location of entity classes.

Application class-

package com.H2DatabaseDemo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages="com.H2DatabaseDemo")
public class H2DatabaseDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(H2DatabaseDemoApplication.class, args);
    }
}

Aauthor Entity-

package com.H2DatabaseDemo.model;

import java.util.List;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;

@Entity
public class Author {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private long id;
    private String title;
    private String body;

    public Author() {}

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }
}

Post entity-

package com.H2DatabaseDemo.model;

import java.awt.List;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

@Entity
public class Post {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private long id;
    private String name;

    public Post() {}

    public Post(long id, String name) {         
        this.id = id;
        this.name = name;           
    }    

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

Here is my project directory structure

here is my pom.xml file-

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.H2DatabaseDemo</groupId>
    <artifactId>H2DatabaseDemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>H2DatabaseDemo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

Stack trace- :: Spring Boot :: (v2.0.4.RELEASE)

2018-09-13 18:00:07.448 INFO 12584 --- [ 2018-09-13 18:00:07.453 INFO 12584 --- [ 2018-09-13 18:00:07.539 INFO 12584 --- [ 2018-09-13 18:00:09.114 INFO 12584 --- [ 2018-09-13 18:00:09.860 INFO 12584 --- [ 2018-09-13 18:00:09.892 INFO 12584 --- [ 2018-09-13 18:00:09.893 INFO 12584 --- [ 2018-09-13 18:00:09.903 INFO 12584 2018-09-13 18:00:10.046 INFO 12584 2018-09-13 18:00:10.047 INFO 12584 2018-09-13 18:00:10.173 INFO 12584 2018-09-13 18:00:10.179 INFO 12584 2018-09-13 18:00:10.188 INFO 12584 2018-09-13 18:00:10.189 INFO 12584 2018-09-13 18:00:10.189 INFO 12584 2018-09-13 18:00:10.189 INFO 12584 2018-09-13 18:00:10.392 INFO 12584 --- [ 2018-09-13 18:00:10.667 INFO 12584 --- [ 2018-09-13 18:00:10.733 INFO 12584 --- [ 2018-09-13 18:00:10.754 INFO 12584 --- [ name: default ...] 2018-09-13 18:00:10.863 INFO 12584 --- [ 2018-09-13 18:00:10.864 INFO 12584 --- [ 2018-09-13 18:00:10.910 INFO 12584 --- [ 2018-09-13 18:00:11.034 INFO 12584 --- [ 2018-09-13 18:00:11.581 INFO 12584 --- [ 2018-09-13 18:00:11.585 INFO 12584 --- [ 2018-09-13 18:00:11.700 INFO 12584 --- [ 2018-09-13 18:00:12.010 INFO 12584 --- [ 2018-09-13 18:00:12.060 WARN 12584 --- [ 2018-09-13 18:00:12.147 INFO 12584 --- [ 2018-09-13 18:00:12.149 INFO 12584 --- [ 2018-09-13 18:00:12.183 INFO 12584 --- [ 2018-09-13 18:00:12.183 INFO 12584 --- [ 2018-09-13 18:00:12.558 INFO 12584 --- [ 2018-09-13 18:00:12.560 INFO 12584 --- [ 2018-09-13 18:00:12.565 INFO 12584 --- [ 2018-09-13 18:00:12.605 INFO 12584 --- [ 2018-09-13 18:00:12.610 INFO 12584 --- [ main] c.H.H2DatabaseDemoApplication : Starting H2DatabaseDemoApplication on DESKTOP-7NILS0D with PID 12584 (D:\springCourse\H2DatabaseDemo\target\classes started by Mrugesh in D:\springCourse\H2DatabaseDemo) main] c.H.H2DatabaseDemoApplication : No active profile set, falling back to default profiles: default main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@17c1bced: startup date [Thu Sep 13 18:00:07 IST 2018]; root of context hierarchy main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$934327a5] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http) main] o.apache.catalina.core.StandardService : Starting service [Tomcat] main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.32 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [C:\Program Files\Java\jre1.8.0_171\bin;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:/Program Files/Java/jre1.8.0_171/bin/server;C:/Program Files/Java/jre1.8.0_171/bin;C:/Program Files/Java/jre1.8.0_171/lib/amd64;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files\Intel\iCLS Client\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;c:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\nodejs\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\Git\cmd;C:\Program Files\Microsoft VS Code\bin;C:\Program Files\Microsoft VS Code\bin;C:\Users\Mrugesh\AppData\Roaming\npm;C:\Users\Mrugesh\AppData\Local\Microsoft\WindowsApps;C:\Users\Mrugesh\AppData\Local\GitHubDesktop\bin;C:\eclipse;;.] --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 2516 ms --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/] --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet webServlet mapped to [/console/] --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/] --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/] --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/] --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*] main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. main] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'default' main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [ main] org.hibernate.Version : HHH000412: Hibernate Core {5.2.17.Final} main] org.hibernate.cfg.Environment : HHH000206: hibernate.properties not found main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.0.1.Final} main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect main] o.h.t.schema.internal.SchemaCreatorImpl : HHH000476: Executing import script 'org.hibernate.tool.schema.internal.exec.ScriptSourceInputNonExistentImpl@6bcc3f27' main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default' main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [//favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@17c1bced: startup date [Thu Sep 13 18:00:07 IST 2018]; root of context hierarchy main] aWebConfiguration$JpaWebMvcConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest) main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup main] o.s.j.e.a.AnnotationMBeanExporter : Bean with name 'dataSource' has been autodetected for JMX exposure main] o.s.j.e.a.AnnotationMBeanExporter : Located MBean 'dataSource': registering with JMX server as MBean [com.zaxxer.hikari:name=dataSource,type=HikariDataSource] main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path '' main] c.H.H2DatabaseDemoApplication : Started H2DatabaseDemoApplication in 5.598 seconds (JVM running for 6.203)

You don't need @ComponentScan next to that entities aren't components so they won't be detected by component-scanning. Why do you use a java.awt.List instead of a java.util.List in your entity? — M. Deinum
Your class is not declared as a bean, so its normal that your component scan wouldn't find it, declare your class as @Component — Elhoussine Zennati
can you add @Table(name = "post") and @Table(name = "author") and try, also you may not need @ComponentScan(basePackages="com.H2DatabaseDemo"), when you add @SpringBootApplication over a class then Spring will search all components at and inside that package? — dkb
Please post your pom.xml, your stack trace and eventually your application.properties file. And replace java.awt.List with List as mentioned before — AchillesVan

AchillesVan AchillesVan · Accepted Answer · 2018-09-13T22:47:22

Your entities classes are fine but your H2 console is configured with the default db (testdb if i'm not wrong). You should at least specify the URL in your H2 Console to match your db name or the other way around.

You may try the following approach:

1 In the application.properties file configure H2 console access control:

spring.h2.console.enabled=true
spring.h2.console.path=/h2-console
spring.datasource.url=jdbc:h2:mem:hddemo-app

2 Access the db from http://localhost:8080/h2-console/

3 Inside the H2 Console, Copy and paste jdbc:h2:mem:hddemo-app in the JDBC URL field. Leave the password field empty and click the connect button.

4 You should see the entity you specified in your project as a table.

problem with spring boot component scanning

3 Answers