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 --- [ main] cHH2DatabaseDemoApplication : Starting H2DatabaseDemoApplication on DESKTOP-7NILS0D with PID 12584 (D:\\springCourse\\H2DatabaseDemo\\target\\classes started by Mrugesh in D:\\springCourse\\H2DatabaseDemo) 2018-09-13 18:00:07.453 INFO 12584 --- [ main] cHH2DatabaseDemoApplication : No active profile set, falling back to default profiles: default 2018-09-13 18:00:07.539 INFO 12584 --- [ 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 2018-09-13 18:00:09.114 INFO 12584 --- [ 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) 2018-09-13 18:00:09.860 INFO 12584 --- [ main] osbwembedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http) 2018-09-13 18:00:09.892 INFO 12584 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] 2018-09-13 18:00:09.893 INFO 12584 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.32 2018-09-13 18:00:09.903 INFO 12584 --- [ost-startStop-1] oacatalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in prod uction 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:\\Progra m 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;;.] 2018-09-13 18:00:10.046 INFO 12584 --- [ost-startStop-1] oaccC[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2018-09-13 18:00:10.047 INFO 12584 --- [ost-startStop-1] osweb.context.ContextLoader : Root WebApplicationContext: initialization completed in 2516 ms 2018-09-13 18:00:10.173 INFO 12584 --- [ost-startStop-1] osbwservlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/] 2018-09-13 18:00:10.179 INFO 12584 --- [ost-startStop-1] osbwservlet.ServletRegistrationBean : Servlet webServlet mapped to [/console/ ] 2018-09-13 18:00:10.188 INFO 12584 --- [ost-startStop-1] osbwservlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/ ] 2018-09-13 18:00:10.189 INFO 12584 --- [ost- startStop-1] osbwservlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/ ] 2018-09-13 18:00:10.189 INFO 12584 --- [ost-startStop-1] osbwservlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/ ] 2018-09-13 18:00:10.189 INFO 12584 --- [ost-startStop-1] osbwservlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*] 2018-09-13 18:00:10.392 INFO 12584 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... 2018-09-13 18:00:10.667 INFO 12584 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. 2018-09-13 18:00:10.733 INFO 12584 --- [ main] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'default' 2018-09-13 18:00:10.754 INFO 12584 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [ name: default ...] 2018-09-13 18:00:10.863 INFO 12584 --- [ main] org.hibernate.Version : HHH000412: Hibernate Core {5.2.17.Final} 2018-09-13 18:00:10.864 INFO 12584 --- [ main] org.hibernate.cfg.Environment : HHH000206: hibernate.properties not found 2018-09-13 18:00:10.910 INFO 12584 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.0.1.Final} 2018-09-13 18:00:11.034 INFO 12584 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect 2018-09-13 18:00:11.581 INFO 12584 --- [ main] ohtschema.internal.SchemaCreatorImpl : HHH000476: Executing import script 'org.hibernate.tool.schema.internal.exec.Script SourceInputNonExistentImpl@6bcc3f27' 2018-09-13 18:00:11.585 INFO 12584 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default' 2018-09-13 18:00:11.700 INFO 12584 --- [ main] oswshandler.SimpleUrlHandlerMapping : Mapped URL path [/ /favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2018-09-13 18:00:12.010 INFO 12584 --- [ main] swsmmaRequestMappingHandlerAdapter : 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 2018-09-13 18:00:12.060 WARN 12584 --- [ 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 2018-09-13 18:00:12.147 INFO 12584 --- [ main] swsmmaRequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest) 2018-09-13 18:00:12.149 INFO 12584 --- [ main] swsmmaRequestMappingHandlerMapping : 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) 2018-09-13 18:00:12.183 INFO 12584 --- [ main] oswshandler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/ ] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2018-09-13 18:00:12.183 INFO 12584 --- [ main] oswshandler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2018-09-13 18:00:12.558 INFO 12584 --- [ main] osjeaAnnotationMBeanExporter : Registering beans for JMX exposure on startup 2018-09-13 18:00:12.560 INFO 12584 --- [ main] osjeaAnnotationMBeanExporter : Bean with name 'dataSource' has been autodetected for JMX exposure 2018-09-13 18:00:12.565 INFO 12584 --- [ main] osjeaAnnotationMBeanExporter : Located MBean 'dataSource': registering with JMX server as MBean [com.zaxxer.hikari:name=dataSource,type=HikariDataSource] 2018-09-13 18:00:12.605 INFO 12584 --- [ main] osbwembedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path '' 2018-09-13 18:00:12.610 INFO 12584 --- [ main] cHH2DatabaseDemoApplication : Started H2DatabaseDemoApplication in 5.598 seconds (JVM running for 6.203)

Answer 1

Try configurate

hibernate.hbm2ddl.auto

value to be create by adding following line in the application.properties.

spring.jpa.hibernate.ddl-auto=create

I have the same problem so I tried this and it works.

Hope this helps.

Answer 2

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.

Answer 3

In Spring you have two annotations for scanning: - ComponentScan for scanning Component annotated classes and generating beans out of them ( https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/context/annotation/ComponentScan.html ), and - EntityScan for generating information for JPA and others for the entities ( https://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/autoconfigure/domain/EntityScan.html )

In your case, since you are trying to generate entitites and not beans/components, you should use @EntityScan .

NB: Spring also supports auto configuration: https://docs.spring.io/spring-boot/docs/current/reference/html/using-boot-auto-configuration.html