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Using Spring-Boot-Starter-Web in combination with ObjectDB

I am implementing a program in Spring-Boot using ObjectDB. To actually use ObjectDB I have followed this approach which is working perfectly.
However, as soon as I want to use `spring-boot-starter-web`` then I am getting the following errors:
dataSource or dataSourceClassName or jdbcUrl is required. at
com.zaxxer.hikari.HikariConfig.validate
I have been fiddling around with parameter jdbc-url in the properties file as mentioned in many posts. Tried to exclude Hikari because probably ObjectDB uses his own connection pooling mechanism. But without any results.
Any ideas on how to solve this error?
I am using the exact same code as in the link. I have added Spring-Actuator in the pom like this:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

In some cases, frameworks that use JPA require specifying a JDBC connection details, including a JDBC driver, which is then passed to the JPA implementation and used by it to access the database. ObjectDB is a JPA implementation that does not access an external database, and therefore, does not need or use a JDBC driver.
As discussed in the comments to the question, a simple workaround is to specify a dummy JDBC driver, which will be passed to ObjectDB and then ignored. It does look weird, but this is the way to go until either ObjectDB implement its own JDBC driver, or the relevant frameworks become more flexible regarding their request of a JDBC driver.

Have you tried this (in the pom.xml?):
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.objectdb</groupId>
<artifactId>objectdb</artifactId>
<version>2.8.4</version>
</dependency>
And don't forget to add the database connection in application.properties:
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=mydbuser
spring.datasource.password=mydbpass
spring.datasource.url=jdbc:....
See https://www.baeldung.com/the-persistence-layer-with-spring-and-jpa for more details.

Creating a MongoDB database through the defined classes / documents in Java Spring

I want to be able to use my Entities classes / documents created with Java Spring in order to create my MongoDB Database at Runtime abd see the different fields of the documents and collections and this automatically when running my spring boot application.
I use the property in my application.properties.
hibernate.ogm.datastore.create_database=true
and as a dependency in pom.xml :
<dependency>
<groupId>org.hibernate.ogm</groupId>
<artifactId>hibernate-ogm-mongodb</artifactId>
<version>5.4.1.Final</version>
</dependency>
The application launches but the associated database is not created, What am i missing here,
Thank you.

Spring Boot switch between multiple databases (data-sources)

I have a spring boot REST API application for a project with 2 different setups ( =2 different jars). Both need to be realized, but I have no idea on how to do it or what the best way would be.
Both setups need to have a connection with an online database (on a server; AWS) and a connection with an offline or local database (running on the machine/pc itself). It is the offline or local connection that is different between both setups.
Setup 1:
When the application is started it needs to connect to the online database. When an error occurs or connection to the online database is lost, it needs to connect to the offline/local database.
It is not required that that it will reconnect with the online database after an error occurred or the connection was lost.
Setup 2:
When the application is started it needs to connect to both the online and the offline database. So when the user does a post to the REST API, both the online and the offline database need to be updated (unless an error occurs or the connection to the online database is lost). If the user just does a get request, it is preferred to get the data from the online database, unless an error occurs or the connection to the online database is lost, than it can use the offline database.
It is not required that that it will reconnect with the online database after an error occurred or the connection was lost, but in this setup it would be nice.
Synchronizing the data after connection has been established again isn't required either (but would maybe be a nice feature).
I have seen a similar post where the solution was to use ha-jdbc but it is an old post... Maven just doesn't find the dependency when I try adding it to my pom.xml file.
After some more searching and trying I was able to add ha-jdbc to my pom.xml. What I had to do was add a repository that contained ha-jdbc.
<project>
<repositories>
<repository>
<id>jbossrepository</id>
<name>jbossrepository</name>
<url>https://repository.jboss.org/nexus/content/repositories/thirdparty-releases/</url>
</repository>
</repositories>
<dependency>
<dependency>
<groupId>net.sf.ha-jdbc</groupId>
<artifactId>ha-jdbc</artifactId>
<version>3.0.3</version>
</dependency>
</dependency>
</project>
Yet to see if I can get it to work and if it is what I am looking for...
ha-jdbc isn't worth trying, one error or problem after the other, it's just old java too...
Versions:
- java: 1.8
- org.springframework.boot (spring-boot-starter-parent): 2.1.8.RELEASE
- Database (online & offline): PostgreSQL 11.5

Take a look this example code. There you can find already implemented a working solution.
The logic behind it is EnableJpaRepositories which enables it based on packages (basePackages)

How does a service that deployed in the spring-cloud-dataflow-server connect to another database instead of the database that the dataflow-sever use?

The case is that I have launched both Spring Cloud Data Flow Server and Shell apps in my local machine, and they all used the H2 memory database to store the tasks and jobs defination.
When I deployed the application that Used a H2 as the database to read data, it works perfect fine.
But when I want to deploy and run the application that read data from a local postgresql database, it just could not find it, and will then use the H2 again.
I have add postgresql dependency in my pom and also configure the properties in the application.properties , it works fine with spring batch in my local Intelij.
So my question is that how could I make my application still read data from the postgresql after it been deployed in the spring-cloud-data-flow-server? Thanks.
Configuration info:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version
<spring.cloud.task.version>2.0.0.RELEASE</spring.cloud.task.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-batch</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-task-core</artifactId>
<version>${spring.cloud.task.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-task-batch</artifactId>
<version>${spring.cloud.task.version}</version>
</dependency>

You can control what datasource should be configured to SCDF, Tasks, Task-launcher, and even Composed Task Runner. The documentation for these options could be useful.
In your case, though, it sounds like you have 2 different databases: one for SCDF and the other for the Task that SCDF launches, which should be a pretty straightforward setup as long as the datasource properties are configured correctly on both the Boot apps.
It could be that either there's no Postgres driver in the classpath or the datasource properties aren't configured correctly. Review the docs of the connection properties for the supported databases - you could double check for correctness.

Use embedded database for test in spring boot

I have a spring boot application, it has a couple of #Entity classes and #RepositoryRestResource repositort interfaces for them. Now I want to write some tests, where I can check that I can add a new record into my database using those repositories, but I don't want to use my configured MySQL database for it, but instead I want to use some embedded db like H2. At the moment I have an application.properties file, which looks like this:
spring.jpa.hibernate.ddl-auto=create
spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=qwerty123
Question: How do I configure my app to use other db for tests? I have no xml in my project, everything is based on annotations. I tried to define #Configuration class with #Bean to create DataSource and then use it with #ContextConfiguration annotation on test class, but it says that it can't load context.

If you are using a Maven project, you can add a application.properties file into your src/test/resources, for example with the following content.
# Create DDL
spring.jpa.hibernate.ddl-auto=create
# H2 in local file system allowing other simultaneous connections
spring.datasource.url=jdbc:h2:~/test;AUTO_SERVER=TRUE
Also, you need to include H2 as dependency (pom.xml):
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.4.193</version>
</dependency>

Spring Boot provides 2 magic annotations related to JPA autoconfigs for tests: #DataJpaTest and #AutoConfigureTestDatabase.
The javadoc says:
By default, tests annotated with #DataJpaTest will use an embedded
in-memory database (replacing any explicit or usually auto-configured
DataSource). The #AutoConfigureTestDatabase annotation can be used to
override these settings.
If you are looking to load your full application configuration, but
use an embedded database, you should consider #SpringBootTest combined
with #AutoConfigureTestDatabase rather than this annotation.
So, the only thing you absolutely need is a dependency in your pom file:
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>test</scope>
</dependency>
That's it. However, spring boot spec also has 2 useful caveats:
You need not provide any connection URLs. You need only include a
build dependency to the embedded database that you want to use.
If you are using this feature in your tests, you may notice that the
same database is reused by your whole test suite regardless of the
number of application contexts that you use. If you want to make sure
that each context has a separate embedded database, you should set
spring.datasource.generate-unique-name to true.
And another one:
If, for whatever reason, you do configure the connection URL for an
embedded database, take care to ensure that the database’s automatic
shutdown is disabled. If you use H2, you should use
DB_CLOSE_ON_EXIT=FALSE to do so. If you use HSQLDB, you should ensure
that shutdown=true is not used. Disabling the database’s automatic
shutdown lets Spring Boot control when the database is closed, thereby
ensuring that it happens once access to the database is no longer
needed.
That's almost all you need to know about Spring Boot and embedded DBs. I see absolutely no reason to use the scope of dependency other than test, unless you actually intentionally configure an embedded DB for your application runtime. Believe it or not H2 jar alone takes 1.8M inside your fat jar. In the world on granular microservices, serverless and lambda functions it does matter what you put inside your apps.
I would also recommend checking the options in #AutoConfigureTestDatabase. I use it with #SpringBootTest, but it can also be used with some other annotations, namely #DataJpaTest, both mentioned above:

You will need to use Spring Profiles - https://docs.spring.io/spring-boot/docs/current/reference/html/howto-properties-and-configuration.html#howto-set-active-spring-profiles
You will define an active profile using "spring.profiles.active = development" and then including H2 in your development profile.
The examples use YAML, but they work in standard properties files as well.