Spring boot H2 database not found & not created by Liquibase - spring

Question

I'm trying to create a Spring Boot application with an embedded database (H2) and create data with liquibase on application startup, but absolutely nothing is working.
When I go to http://localhost:8080/h2-console/ and try to log into jdbc:h2:mem:testdb I get
Database "mem:testdb" not found, either pre-create it or allow remote database creation (not recommended in secure environments) [90149-200] 90149/90149 (Help).
Here's my resources/application.properties:
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true
spring.liquibase.change-log=classpath:/db/changelog/changelog-master.xml
logging.level.liquibase = INFO
Here's my pom.xml:
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.test</groupId>
<artifactId>test</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>test</name>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.liquibase</groupId>
<artifactId>liquibase-core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.4.200</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

Answer 1

To configure H2 database automatically with given DB properties in application.properties, H2ConsoleAutoConfiguration class should be fired.
It is not creating your required database testdb, because a dependency spring-boot-starter-data-jpa is missing in your pom.xml, to auto configure the H2 database. Once you add that dependency, your code works well.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
Once after adding this, you will observe a H2ConsoleAutoConfiguration executed in logs like below
o.s.b.a.h2.H2ConsoleAutoConfiguration : H2 console available at '/h2-console'. Database available at 'jdbc:h2:mem:testdb'

Answer 2

Somehow , If you want to connect via console, Spring is unable to create a PHYSICAL file testdb.mv.db in root folder, i.e C:/USERS/testdb.mv.db. I went to C:/Users/SHEKHAR , and created a New > text file ( don't save it untill you rename it to testdb.mv.db or test.mv.db. Restart Springboot, "Test Connection" is Green and Connect , takes me to Console GUI.