Failed to configure a DataSource in Spring Boot with H2 in-memory database

I am developing a Spring Boot application with H2 as an embedded in-memory database. I'm facing an issue while trying to access the H2 console. Whenever I navigate to http://localhost:8080/h2-console, it prompts me for a username and password.

The console output:

2023-08-03T19:41:47.901+03:00  INFO 5176 --- [           main] c.e.a.AlbacamiereaApplication            : Starting AlbacamiereaApplication using Java 17.0.5 with PID 5176 (C:\albacamierea\target\classes started by Robert in C:\albacamierea)
2023-08-03T19:41:47.916+03:00  INFO 5176 --- [           main] c.e.a.AlbacamiereaApplication            : No active profile set, falling back to 1 default profile: "default"
2023-08-03T19:41:50.102+03:00  INFO 5176 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2023-08-03T19:41:50.167+03:00  INFO 5176 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 38 ms. Found 0 JPA repository interfaces.
2023-08-03T19:41:51.805+03:00  INFO 5176 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-08-03T19:41:51.809+03:00  INFO 5176 --- [           main] o.a.catalina.core.AprLifecycleListener   : Loaded Apache Tomcat Native library [2.0.3] using APR version [1.7.2].
2023-08-03T19:41:51.851+03:00  INFO 5176 --- [           main] o.a.catalina.core.AprLifecycleListener   : OpenSSL successfully initialized [OpenSSL 3.0.8 7 Feb 2023]
2023-08-03T19:41:51.891+03:00  INFO 5176 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-08-03T19:41:51.892+03:00  INFO 5176 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.11]
2023-08-03T19:41:52.247+03:00  INFO 5176 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-08-03T19:41:52.248+03:00  INFO 5176 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 4149 ms
2023-08-03T19:41:52.757+03:00  INFO 5176 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2023-08-03T19:41:53.629+03:00  INFO 5176 --- [           main] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Added connection conn0: url=jdbc:h2:mem:d48ab7e7-383a-4245-846e-d273ef5237bd user=SA
2023-08-03T19:41:53.637+03:00  INFO 5176 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2023-08-03T19:41:53.884+03:00  INFO 5176 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2023-08-03T19:41:54.170+03:00  INFO 5176 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 6.2.6.Final
2023-08-03T19:41:54.178+03:00  INFO 5176 --- [           main] org.hibernate.cfg.Environment            : HHH000406: Using bytecode reflection optimizer
2023-08-03T19:41:54.854+03:00  INFO 5176 --- [           main] o.h.b.i.BytecodeProviderInitiator        : HHH000021: Bytecode provider name : bytebuddy
2023-08-03T19:41:55.528+03:00  INFO 5176 --- [           main] o.s.o.j.p.SpringPersistenceUnitInfo      : No LoadTimeWeaver setup: ignoring JPA class transformer
2023-08-03T19:41:56.089+03:00  INFO 5176 --- [           main] o.h.b.i.BytecodeProviderInitiator        : HHH000021: Bytecode provider name : bytebuddy
2023-08-03T19:41:57.195+03:00  INFO 5176 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2023-08-03T19:41:57.221+03:00  INFO 5176 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2023-08-03T19:41:57.358+03:00  WARN 5176 --- [           main] JpaBaseConfiguration$JpaWebConfiguration : 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
2023-08-03T19:41:58.582+03:00  WARN 5176 --- [           main] .s.s.UserDetailsServiceAutoConfiguration : 

Using generated security password: dab22a6d-fca6-4e5d-9796-8f4d30c2c9b5

I have tried accessing the H2 console with a blank username and password, as well as with the default "SA" username and no password, but it still doesn't work.

It seems that you have Spring Security enabled but not explicitly allowed the path to your H2 endpoint.

A possible SecurityFilterChain setup for H2 only (should be positioned in front of the other FilterChains via @Orderannotation):

@Bean
@Order(5)
// @Profile("development")
public SecurityFilterChain h2FilterChain(
        HttpSecurity http,
        @Value("${spring.h2.console.path:/h2-console}") String h2ConsolePath) throws Exception {

    return http
            .securityMatchers(matchers -> matchers
                    /* https://github.com/spring-projects/spring-security/issues/12546#issuecomment-1382891839 */
                    .requestMatchers(AntPathRequestMatcher.antMatcher(h2ConsolePath + "/**")))

            .authorizeHttpRequests(authorize -> authorize.anyRequest().permitAll())

            /* The H2 console runs in a frameset. Thus, we need to set 'X-Frame-Options' from 'deny' to 'sameOrigin'. */
            .headers(header -> header.frameOptions(HeadersConfigurer.FrameOptionsConfig::sameOrigin))

            /* Otherwise login into H2 won't work. */
            .csrf(CsrfConfigurer::disable)

            .build()
}

Make sure to set the h2-console value in the properties correctly.