Error when trying to connect multiple databases

[djeannerod]

Hello everyone here,

first, id' like to thank the developers for this great and useful project !
I'm trying to connect several databases, on the same db2rest instance, following the doc: https://db2rest.com/docs/multidb/connect-multiple-db
I tried the two different ways of configuring, using the json configuration variable, or the yaml configuration file application.yml.
In both cases, I have the same java error.
I'm using db2rest-1.6.8.jar on a Windows server.
My auth.yml is Ok and working, tested with a simple configuration with only one DB.

Am I missing something in my conf ? Is it a bug ?

First configuration tried (Powershell script on Windows):

Write-Host "Starting db2rest"
$env:SPRING_APPLICATION_JSON = '{"app":{"databases":[{"id":"db1","type":"MYSQL","url":"jdbc:mysql://127.0.0.1:3306/demov5?zeroDateTimeBehavior=CONVERT_TO_NULL","username":"fake_user","password":"fake_password"}]}}'
$env:AUTH_DATA_SOURCE = "file://D:/db2rest/auth.yml"; 
$env:ENABLE_AUTH = "true";
$env:AUTH_PROVIDER = "apiKey";
$env:SERVER_PORT = 6001;
java -jar ./db2rest-1.6.8.jar

Log

Starting db2rest

    ____  ____  ____ ____  ____  _____ ____ _____  ____
   / / / |  _ \| __ )___ \|  _ \| ____/ ___|_   _| \ \ \
  | | |  | | | |  _ \ __) | |_) |  _| \___ \ | |    | | |
 < < <   | |_| | |_) / __/|  _ <| |___ ___) || |     > > >
  | | |  |____/|____/_____|_| \_\_____|____/ |_|    | | |
   \_\_\ ========================================= /_/_/
   +---------------------------------------------------+
   |:: db2rest version ::     v1.6.8               |
   |:: Spring-Boot version ::     v3.5.5               |
   |:: Visit db2rest website :: [https://db2rest.com/] |
   +---------------------------------------------------+
2026-01-12T12:38:29.496+01:00  INFO 8388 --- [           main] com.homihq.db2rest.Db2restApplication    : Starting Db2restApplication v1.6.8 using Java 25.0.1 with PID 8388 (D:\db2rest\db2rest-1.6.8.jar started by infra_admen in D:\db2rest)
2026-01-12T12:38:29.500+01:00  INFO 8388 --- [           main] com.homihq.db2rest.Db2restApplication    : No active profile set, falling back to 1 default profile: "default"
2026-01-12T12:38:31.414+01:00  INFO 8388 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port 6001 (http)
2026-01-12T12:38:31.435+01:00  INFO 8388 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2026-01-12T12:38:31.437+01:00  INFO 8388 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.44]
2026-01-12T12:38:31.480+01:00  INFO 8388 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2026-01-12T12:38:31.482+01:00  INFO 8388 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1917 ms
2026-01-12T12:38:31.737+01:00  INFO 8388 --- [           main] c.homihq.db2rest.auth.AuthConfiguration  : Initializing file auth data provider
2026-01-12T12:38:31.906+01:00  INFO 8388 --- [           main] c.homihq.db2rest.auth.AuthConfiguration  : ** Auth enabled. Initializing auth components.
2026-01-12T12:38:32.059+01:00  INFO 8388 --- [           main] c.h.db2rest.multidb.DatabaseProperties   : Database configuration found.
2026-01-12T12:38:32.060+01:00  INFO 8388 --- [           main] c.h.db2rest.multidb.DatabaseProperties   : JDBC Url found : true
2026-01-12T12:38:32.066+01:00  WARN 8388 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'jdbcFunctionService' defined in URL [jar:nested:/D:/db2rest/db2rest-1.6.8.jar/!BOOT-INF/lib/rdbms-support-1.6.8.jar!/com/homihq/db2rest/jdbc/core/service/JdbcFunctionService.class]: Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'jdbcManager' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
2026-01-12T12:38:32.072+01:00  INFO 8388 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2026-01-12T12:38:32.284+01:00  INFO 8388 --- [           main] .s.b.a.l.ConditionEvaluationReportLogger :

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2026-01-12T12:38:32.310+01:00 ERROR 8388 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'jdbcFunctionService' defined in URL [jar:nested:/D:/db2rest/db2rest-1.6.8.jar/!BOOT-INF/lib/rdbms-support-1.6.8.jar!/com/homihq/db2rest/jdbc/core/service/JdbcFunctionService.class]: Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'jdbcManager' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:804) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:240) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1395) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1232) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:569) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:339) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:373) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1222) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1188) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1123) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:987) ~[spring-context-6.2.10.jar!/:6.2.10]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:627) ~[spring-context-6.2.10.jar!/:6.2.10]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:318) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1361) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1350) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at com.homihq.db2rest.Db2restApplication.main(Db2restApplication.java:15) ~[!/:1.6.8]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
        at org.springframework.boot.loader.launch.Launcher.launch(Launcher.java:102) ~[db2rest-1.6.8.jar:1.6.8]
        at org.springframework.boot.loader.launch.Launcher.launch(Launcher.java:64) ~[db2rest-1.6.8.jar:1.6.8]
        at org.springframework.boot.loader.launch.JarLauncher.main(JarLauncher.java:40) ~[db2rest-1.6.8.jar:1.6.8]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jdbcManager' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:489) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1375) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1205) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:569) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:339) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:373) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1690) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1635) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:913) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 26 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:200) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiateWithFactoryMethod(SimpleInstantiationStrategy.java:89) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:169) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 39 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:489) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1375) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1205) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:569) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:339) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:373) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.resolveBeanReference(ConfigurationClassEnhancer.java:432) ~[spring-context-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:403) ~[spring-context-6.2.10.jar!/:6.2.10]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.dataSource(<generated>) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration.jdbcManager(DbServiceConfiguration.java:104) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.CGLIB$jdbcManager$6(<generated>) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$FastClass$$1.invoke(<generated>) ~[!/:1.6.8]
        at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:258) ~[spring-core-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:400) ~[spring-context-6.2.10.jar!/:6.2.10]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.jdbcManager(<generated>) ~[!/:1.6.8]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:172) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 42 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:200) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiateWithFactoryMethod(SimpleInstantiationStrategy.java:89) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:169) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 63 common frames omitted
Caused by: java.lang.IllegalArgumentException: maxPoolSize cannot be less than 1
        at com.zaxxer.hikari.HikariConfig.setMaximumPoolSize(HikariConfig.java:257) ~[HikariCP-6.3.2.jar!/:na]
        at com.homihq.db2rest.config.DbServiceConfiguration.buildDataSource(DbServiceConfiguration.java:85) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration.buildDataSources(DbServiceConfiguration.java:72) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration.dataSource(DbServiceConfiguration.java:50) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.CGLIB$dataSource$1(<generated>) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$FastClass$$1.invoke(<generated>) ~[!/:1.6.8]
        at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:258) ~[spring-core-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:400) ~[spring-context-6.2.10.jar!/:6.2.10]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.dataSource(<generated>) ~[!/:1.6.8]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:172) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 66 common frames omitted

Second configuration tested - application.yml

app:
  databases:
    - id: db1
      type: MYSQL
      url: jdbc:mysql://127.0.0.1:3306/demov5?zeroDateTimeBehavior=CONVERT_TO_NULL
      username: fake_user
      password: "fake_password"

Powershell script

Write-Host "Starting db2rest"
$env:AUTH_DATA_SOURCE = "file://D:/db2rest/auth.yml"; 
$env:ENABLE_AUTH = "true";
$env:AUTH_PROVIDER = "apiKey";
$env:SERVER_PORT = 6001;

java -jar ./db2rest-1.6.8.jar

Log

Starting db2rest

    ____  ____  ____ ____  ____  _____ ____ _____  ____
   / / / |  _ \| __ )___ \|  _ \| ____/ ___|_   _| \ \ \
  | | |  | | | |  _ \ __) | |_) |  _| \___ \ | |    | | |
 < < <   | |_| | |_) / __/|  _ <| |___ ___) || |     > > >
  | | |  |____/|____/_____|_| \_\_____|____/ |_|    | | |
   \_\_\ ========================================= /_/_/
   +---------------------------------------------------+
   |:: db2rest version ::     v1.6.8               |
   |:: Spring-Boot version ::     v3.5.5               |
   |:: Visit db2rest website :: [https://db2rest.com/] |
   +---------------------------------------------------+
2026-01-12T12:37:36.901+01:00  INFO 4472 --- [           main] com.homihq.db2rest.Db2restApplication    : Starting Db2restApplication v1.6.8 using Java 25.0.1 with PID 4472 (D:\db2rest\db2rest-1.6.8.jar started by infra_admen in D:\db2rest)
2026-01-12T12:37:36.906+01:00  INFO 4472 --- [           main] com.homihq.db2rest.Db2restApplication    : No active profile set, falling back to 1 default profile: "default"
2026-01-12T12:37:38.763+01:00  INFO 4472 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port 6001 (http)
2026-01-12T12:37:38.781+01:00  INFO 4472 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2026-01-12T12:37:38.782+01:00  INFO 4472 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.44]
2026-01-12T12:37:38.826+01:00  INFO 4472 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2026-01-12T12:37:38.828+01:00  INFO 4472 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1856 ms
2026-01-12T12:37:39.077+01:00  INFO 4472 --- [           main] c.homihq.db2rest.auth.AuthConfiguration  : Initializing file auth data provider
2026-01-12T12:37:39.230+01:00  INFO 4472 --- [           main] c.homihq.db2rest.auth.AuthConfiguration  : ** Auth enabled. Initializing auth components.
2026-01-12T12:37:39.373+01:00  INFO 4472 --- [           main] c.h.db2rest.multidb.DatabaseProperties   : Database configuration found.
2026-01-12T12:37:39.374+01:00  INFO 4472 --- [           main] c.h.db2rest.multidb.DatabaseProperties   : JDBC Url found : true
2026-01-12T12:37:39.378+01:00  WARN 4472 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'jdbcFunctionService' defined in URL [jar:nested:/D:/db2rest/db2rest-1.6.8.jar/!BOOT-INF/lib/rdbms-support-1.6.8.jar!/com/homihq/db2rest/jdbc/core/service/JdbcFunctionService.class]: Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'jdbcManager' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
2026-01-12T12:37:39.384+01:00  INFO 4472 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2026-01-12T12:37:39.596+01:00  INFO 4472 --- [           main] .s.b.a.l.ConditionEvaluationReportLogger :

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2026-01-12T12:37:39.626+01:00 ERROR 4472 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'jdbcFunctionService' defined in URL [jar:nested:/D:/db2rest/db2rest-1.6.8.jar/!BOOT-INF/lib/rdbms-support-1.6.8.jar!/com/homihq/db2rest/jdbc/core/service/JdbcFunctionService.class]: Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'jdbcManager' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:804) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:240) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1395) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1232) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:569) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:339) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:373) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1222) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1188) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1123) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:987) ~[spring-context-6.2.10.jar!/:6.2.10]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:627) ~[spring-context-6.2.10.jar!/:6.2.10]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:318) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1361) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1350) ~[spring-boot-3.5.5.jar!/:3.5.5]
        at com.homihq.db2rest.Db2restApplication.main(Db2restApplication.java:15) ~[!/:1.6.8]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
        at org.springframework.boot.loader.launch.Launcher.launch(Launcher.java:102) ~[db2rest-1.6.8.jar:1.6.8]
        at org.springframework.boot.loader.launch.Launcher.launch(Launcher.java:64) ~[db2rest-1.6.8.jar:1.6.8]
        at org.springframework.boot.loader.launch.JarLauncher.main(JarLauncher.java:40) ~[db2rest-1.6.8.jar:1.6.8]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jdbcManager' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:489) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1375) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1205) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:569) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:339) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:373) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1690) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1635) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:913) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 26 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.homihq.db2rest.jdbc.JdbcManager]: Factory method 'jdbcManager' threw exception with message: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:200) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiateWithFactoryMethod(SimpleInstantiationStrategy.java:89) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:169) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 39 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/homihq/db2rest/config/DbServiceConfiguration.class]: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:489) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1375) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1205) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:569) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:529) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:339) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:373) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.resolveBeanReference(ConfigurationClassEnhancer.java:432) ~[spring-context-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:403) ~[spring-context-6.2.10.jar!/:6.2.10]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.dataSource(<generated>) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration.jdbcManager(DbServiceConfiguration.java:104) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.CGLIB$jdbcManager$20(<generated>) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$FastClass$$1.invoke(<generated>) ~[!/:1.6.8]
        at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:258) ~[spring-core-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:400) ~[spring-context-6.2.10.jar!/:6.2.10]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.jdbcManager(<generated>) ~[!/:1.6.8]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:172) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 42 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception with message: maxPoolSize cannot be less than 1
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:200) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiateWithFactoryMethod(SimpleInstantiationStrategy.java:89) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:169) ~[spring-beans-6.2.10.jar!/:6.2.10]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 63 common frames omitted
Caused by: java.lang.IllegalArgumentException: maxPoolSize cannot be less than 1
        at com.zaxxer.hikari.HikariConfig.setMaximumPoolSize(HikariConfig.java:257) ~[HikariCP-6.3.2.jar!/:na]
        at com.homihq.db2rest.config.DbServiceConfiguration.buildDataSource(DbServiceConfiguration.java:85) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration.buildDataSources(DbServiceConfiguration.java:72) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration.dataSource(DbServiceConfiguration.java:50) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.CGLIB$dataSource$23(<generated>) ~[!/:1.6.8]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$FastClass$$1.invoke(<generated>) ~[!/:1.6.8]
        at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:258) ~[spring-core-6.2.10.jar!/:6.2.10]
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:400) ~[spring-context-6.2.10.jar!/:6.2.10]
        at com.homihq.db2rest.config.DbServiceConfiguration$$SpringCGLIB$$0.dataSource(<generated>) ~[!/:1.6.8]
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.lambda$instantiate$0(SimpleInstantiationStrategy.java:172) ~[spring-beans-6.2.10.jar!/:6.2.10]
        ... 66 common frames omitted

[thadguidry]

For some reason in your environment the Hikari connection pool library that we use in code is defaulting to a pool size of 0 or -1 on your Windows system? weird, its actually 10 by default.
Try to set the Spring env variable using JVM option syntax (-D property overrides values in application.properties or application.yaml) when you run the jar.

java -Dspring.datasource.hikari.maximumPoolSize=20 -jar ./db2rest-1.6.8.jar

If you want to get lots of debug info on the whole configuration you can also pass -Ddebug=true like so:

java -Dspring.datasource.hikari.maximumPoolSize=20 -Ddebug=true -jar ./db2rest-1.6.8.jar

[djeannerod]

Thank you for your answer. I tried and have now this error:

java -Dspring.datasource.hikari.maximumPoolSize=20 -jar ./db2rest-1.6.8.jar
Error: Could not find or load main class .datasource.hikari.maximumPoolSize=20
Caused by: java.lang.ClassNotFoundException: /datasource/hikari/maximumPoolSize=20

[djeannerod]

I'm using the JDK 25, I don't know if it could be important as the requirement is 21+

java -version
java version "25.0.1" 2025-10-21 LTS
Java(TM) SE Runtime Environment (build 25.0.1+8-LTS-27)
Java HotSpot(TM) 64-Bit Server VM (build 25.0.1+8-LTS-27, mixed mode, sharing)

[thadguidry]

OK, I've reproduced the issue.
It's basically quite simple. Your SPRING_APPLICATION_JSON doesn't include the maxConnections: 10 and actually it should not, it should be defaulted in our code somehow for even multi database config, but currently it's not. That's a bug.

For now, use this revised script and hack as you need. Auth is disabled for my testing, so you can add those back into this script (seriously awesome help for it came from Grok AI here after about 1 hour of troubleshooting and verifying our own sourcecode).
I've enabled more logging in case you want to inspect more.

db2rest_start.ps1

$json = @'
{
  "logging": {
    "level": {
      "com.zaxxer.hikari": "TRACE",
      "com.zaxxer.hikari.HikariConfig": "TRACE"
    }
  },
  "app": {
    "databases": [
      {
        "id": "db1",
        "type": "MYSQL",
        "url": "jdbc:mysql://127.0.0.1:3306/demov5?zeroDateTimeBehavior=CONVERT_TO_NULL",
        "username": "fake_user",
        "password": "fake_password",
        "maxConnections": 10
      }
    ]
  }
}
'@

$env:SPRING_APPLICATION_JSON = $json
$env:ENABLE_AUTH = "false"
$env:SERVER_PORT = 6001

Write-Host "Starting db2rest with Hikari DEBUG logging..."
java -jar ./db2rest-1.6.8.jar

@kdhrubo this is a bug in our code somewhere for multi database config. It's not setting HikariConfig like it does with non-multi database, and thus doesn't get the regular HikariConfig defaults (like maximumPoolSize=10 in Hikari source for builder).
FIX: we should use the same builder for multi database for DatabaseConnectionDetail object or something?

[djeannerod]

Thanks a lot for your answer, the workaround is working for me !
I tried to add maxConnections in the JSON, but wasn't in the right path.

Thanks also for your responsiveness