# JDBC Connection to DataHub **URL:** https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696 **Category:** Forum **Tags:** jdbc, dremio, cumulocity, datahub **Created:** [June 21, 2024, 7:51am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696 "2024-06-21T07:51:32Z") **Posts on this page:** 10 **Page:** 1
### Author: ![David.Richter](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@David.Richter](https://community.cumulocity.com/u/David.Richter) #### Post date: [June 21, 2024, 7:51am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/1 "2024-06-21T07:51:33Z")
I try to establish a JDBC connection in my microservice to the Dremio DataHub but it ends up with error message `CONNECTION : SSL negotiation failed` Here the steps I do. 1. I downloaded the JDBC driver from the website that are recommended. I used the newest version [Index of jdbc-driver/25.0.0-202404051521110861-ed9515a8/](https://download.dremio.com/jdbc-driver/25.0.0-202404051521110861-ed9515a8/). I put the file in a libs directory in my project root. 2. I add this driver to my pom.xml ```auto com.dremio dremio-jdbc-driver 25.0.0 system ${project.basedir}/libs/dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar ``` 1. I put the following into my application.properties: ```auto spring.datasource.url=jdbc:dremio:direct=datahub.emea.cumulocity.com:31010;ssl=true spring.datasource.username=${C8Y_BOOTSTRAP_TENANT}/${DREMIO_USERNAME} spring.datasource.password=${DREMIO_PASSWORD} spring.datasource.driver-class-name=com.dremio.jdbc.Driver ``` 1. I setup all enviroenment variables (I also check, all variables are set) 2. I try to check the connection ```auto @Service class DremioMeasurementService(@Autowired private val dataSource: DataSource) { private val jdbcTemplate: JdbcTemplate = JdbcTemplate(dataSource) @PostConstruct fun init() { try { dataSource.connection.use { connection -> println("Successfully connected to Dremio: ${connection.metaData.url}") } } catch (ex: Exception) { println("Failed to connect to Dremio: ${ex.message}") } } } ``` Have someone any idea what I do wrong or if I forgot something? The stacktrace I got is this: ```auto java.sql.SQLException: Failure in connecting to Dremio: cdjd.com.dremio.exec.rpc.ConnectionFailedException: CONNECTION : SSL negotiation failed at com.dremio.jdbc.impl.DremioExceptionMapper.map(DremioExceptionMapper.java:73) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at com.dremio.jdbc.impl.DremioConnectionImpl.(DremioConnectionImpl.java:102) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at com.dremio.jdbc.impl.DremioJdbc41Factory.newConnection(DremioJdbc41Factory.java:66) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at com.dremio.jdbc.impl.DremioFactory.newConnection(DremioFactory.java:61) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.org.apache.calcite.avatica.UnregisteredDriver.connect(UnregisteredDriver.java:138) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at com.dremio.jdbc.Driver.connect(Driver.java:76) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.pool.HikariPool.(HikariPool.java:115) ~[HikariCP-4.0.3.jar:na] at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-4.0.3.jar:na] at com.example.microservices.dataintegration.measurment.adapter.dremio.DremioMeasurementService.init(DremioMeasurementService.kt:19) ~[classes/:na] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na] at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na] at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na] at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:389) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:333) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:157) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:440) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1796) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955) ~[spring-beans-5.3.30.jar:5.3.30] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:921) ~[spring-context-5.3.30.jar:5.3.30] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.30.jar:5.3.30] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.17.jar:2.7.17] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732) ~[spring-boot-2.7.17.jar:2.7.17] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:409) ~[spring-boot-2.7.17.jar:2.7.17] at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.17.jar:2.7.17] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300) ~[spring-boot-2.7.17.jar:2.7.17] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1289) ~[spring-boot-2.7.17.jar:2.7.17] at com.example.microservices.dataintegration.DataIntegrationApplicationKt.main(DataIntegrationApplication.kt:13) ~[classes/:na] at com.example.microservices.dataintegration.DataIntegrationApplicationKt.main(DataIntegrationApplication.kt) ~[classes/:na] Caused by: cdjd.com.dremio.exec.rpc.ConnectionFailedException: CONNECTION : SSL negotiation failed at cdjd.com.dremio.exec.rpc.ConnectionFailedException.mapException(ConnectionFailedException.java:29) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.com.dremio.exec.client.DremioClient$FutureHandler.connectionFailed(DremioClient.java:914) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.com.dremio.sabot.rpc.user.QueryResultHandler$ChannelClosedHandler.connectionFailed(QueryResultHandler.java:402) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.com.dremio.exec.rpc.BasicClient$ConnectionMultiListener$ConnectionEstablishmentListener.lambda$addNegotiator$0(BasicClient.java:383) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:590) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:557) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:492) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:636) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:629) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:118) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.setHandshakeFailure(SslHandler.java:1985) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.setHandshakeFailure(SslHandler.java:1955) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.handshake(SslHandler.java:2194) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.startHandshakeProcessing(SslHandler.java:2108) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.handlerAdded(SslHandler.java:2090) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.AbstractChannelHandlerContext.callHandlerAdded(AbstractChannelHandlerContext.java:1130) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.DefaultChannelPipeline.callHandlerAdded0(DefaultChannelPipeline.java:609) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.DefaultChannelPipeline.addBefore(DefaultChannelPipeline.java:269) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.DefaultChannelPipeline.addBefore(DefaultChannelPipeline.java:237) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.com.dremio.exec.rpc.BasicClient$ConnectionMultiListener$ConnectionEstablishmentListener.addNegotiator(BasicClient.java:395) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.com.dremio.exec.rpc.BasicClient$ConnectionMultiListener$ConnectionEstablishmentListener.operationComplete(BasicClient.java:327) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.com.dremio.exec.rpc.BasicClient$ConnectionMultiListener$ConnectionEstablishmentListener.operationComplete(BasicClient.java:303) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:590) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:583) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:559) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:492) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:636) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:625) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:105) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:84) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.fulfillConnectPromise(AbstractNioChannel.java:301) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:336) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:776) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at java.base/java.lang.Thread.run(Thread.java:840) ~[na:na] Caused by: cdjd.com.dremio.exec.rpc.RpcException: CONNECTION : SSL negotiation failed at cdjd.com.dremio.exec.client.DremioClient$FutureHandler.connectionFailed(DremioClient.java:909) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] ... 37 common frames omitted Caused by: cdjd.com.dremio.exec.rpc.RpcException: SSL negotiation failed at cdjd.com.dremio.exec.rpc.BasicClient$ConnectionMultiListener$ConnectionEstablishmentListener.lambda$addNegotiator$0(BasicClient.java:385) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] ... 35 common frames omitted Caused by: java.lang.UnsupportedOperationException: sun.misc.Unsafe or java.nio.DirectByteBuffer.(long, int) not available at cdjd.io.netty.util.internal.PlatformDependent.directBuffer(PlatformDependent.java:532) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.buffer.NettyArrowBuf.getDirectBuffer(NettyArrowBuf.java:267) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.buffer.NettyArrowBuf.internalNioBuffer(NettyArrowBuf.java:217) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.toByteBuffer(SslHandler.java:1606) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.wrap(SslHandler.java:1130) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.wrapNonAppData(SslHandler.java:975) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] at cdjd.io.netty.handler.ssl.SslHandler.handshake(SslHandler.java:2192) ~[dremio-jdbc-driver-25.0.0-202404051521110861-ed9515a8.jar:25.0.0-202404051521110861-ed9515a8] ... 26 common frames omitted ``` ---
### Author: ![Stefan\_Witschel](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/stefan_witschel/32/31955_2.png) [@Stefan\_Witschel](https://community.cumulocity.com/u/Stefan_Witschel) #### Post date: [June 21, 2024, 8:03am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/2 "2024-06-21T08:03:47Z")
Hi David, can you try again by using the dremio JDBC driver that is matching your dremio version? You can check the used dremio version in the datahub app → Administration → System status ![image](https://europe1.discourse-cdn.com/flex005/uploads/cumulocity/original/3X/b/9/b9c1930f0877beb820bc3914428b182761890a58.png) The corresponding driver can be downloaded here: [https://download.dremio.com/jdbc-driver/?\_ga=2.109401093.1016122501.1667783452-235854462.1630284576&\_gac=1.258688760.1664550761.CjwKCAjwp9qZBhBkEiwAsYFsb0x4InlcRP7Rv4XsjamZQHhJILHJWOtBOu30xZC1QwvEXF8cPFs1HhoCB-kQAvD\_BwE](https://download.dremio.com/jdbc-driver/?_ga=2.109401093.1016122501.1667783452-235854462.1630284576&_gac=1.258688760.1664550761.CjwKCAjwp9qZBhBkEiwAsYFsb0x4InlcRP7Rv4XsjamZQHhJILHJWOtBOu30xZC1QwvEXF8cPFs1HhoCB-kQAvD_BwE) ---
### Author: ![David.Richter](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@David.Richter](https://community.cumulocity.com/u/David.Richter) #### Post date: [June 21, 2024, 8:41am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/3 "2024-06-21T08:41:42Z")
I don’t have System status in my options but I can see my dremio version here ![grafik](https://europe1.discourse-cdn.com/flex005/uploads/cumulocity/original/3X/a/1/a1241a83b42900c4cf484f2a86255faa472a228a.png) There is no driver for 24.2.9 so I downloaded and try first with 24.2.6 and then with 24.3.0. Both not working. I get the same error. I was also thinking maybe my firewall make bad stuff but after deactivating it I still have the same problems. ---
### Author: ![Tobias\_Riemenschneider](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/tobias_riemenschneider/32/2189_2.png) [@Tobias\_Riemenschneider](https://community.cumulocity.com/u/Tobias_Riemenschneider) #### Post date: [June 21, 2024, 9:38am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/4 "2024-06-21T09:38:08Z")
Hi David, The relevant information is `java.lang.UnsupportedOperationException: sun.misc.Unsafe or java.nio.DirectByteBuffer.(long, int) not available`. This usually comes up when the Dremio’s Legacy JDBC Driver is used with Java 11 or newer (see [Java 11 JDBC support - Dremio](https://community.dremio.com/t/java-11-jdbc-support/5443/22)). This can be solved by adding the parameter `-Dcdjd.io.netty.tryReflectionSetAccessible=true` to your Java runtime when you run the Legacy JDBC driver. Regards, Toby ---
### Author: ![David.Richter](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@David.Richter](https://community.cumulocity.com/u/David.Richter) #### Post date: [June 21, 2024, 11:39am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/5 "2024-06-21T11:39:01Z")
Adding the parameter `-Dcdjd.io.netty.tryReflectionSetAccessible=true` doesn’t help. Still the same problem. ---
### Author: ![Tobias\_Riemenschneider](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/tobias_riemenschneider/32/2189_2.png) [@Tobias\_Riemenschneider](https://community.cumulocity.com/u/Tobias_Riemenschneider) #### Post date: [June 21, 2024, 1:31pm UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/6 "2024-06-21T13:31:11Z")
Ah, you are right! Dremio’s Legacy JDBC Driver already sets that parameter internally if it is missing (see [dremio-oss/client/jdbc/src/main/java/com/dremio/jdbc/Driver.java at 12d7a954966ee5782921a4fbe32cc4568cbf631b · dremio/dremio-oss · GitHub](https://github.com/dremio/dremio-oss/blob/12d7a954966ee5782921a4fbe32cc4568cbf631b/client/jdbc/src/main/java/com/dremio/jdbc/Driver.java#L47)). Which JVM are you using? ---
### Author: ![Tobias\_Riemenschneider](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/tobias_riemenschneider/32/2189_2.png) [@Tobias\_Riemenschneider](https://community.cumulocity.com/u/Tobias_Riemenschneider) #### Post date: [July 2, 2024, 6:36am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/7 "2024-07-02T06:36:53Z")
When using Java 17+, the parameters `--add-opens java.base/java.nio=ALL-UNNAMED --add-opens java.base/jdk.internal.misc=ALL-UNNAMED` are required (see [netty/common/src/main/java/io/netty/util/internal/PlatformDependent0.java at 4.1 · netty/netty · GitHub](https://github.com/netty/netty/blob/4.1/common/src/main/java/io/netty/util/internal/PlatformDependent0.java) and [Suggested modules to open to reflections to not decrease Netty performances - JDK17+ · Issue #12265 · netty/netty · GitHub](https://github.com/netty/netty/issues/12265)). ---
### Author: ![David.Richter](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@David.Richter](https://community.cumulocity.com/u/David.Richter) #### Post date: [July 5, 2024, 1:50pm UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/8 "2024-07-05T13:50:29Z")
Normally I use Java 21 but for testing I go back to Java 17. I add the parameter you give me, which end up in differend: "Unable to determine Dialect to use [name=Dremio Server, majorVersion=24]; user must register resolver or explicitly set ‘hibernate.dialect’ I think the connection problem is now resolved when I get a Hibernate Error message. I guess to resolve this new problem I need to know what kind of dialect dreamio speaks. So I can setup this: spring.jpa.properties.hibernate.dialect=??? inside of my application.properties. Any idea? And is my guess correct? ---
### Author: ![David.Richter](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@David.Richter](https://community.cumulocity.com/u/David.Richter) #### Post date: [July 8, 2024, 6:01am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/9 "2024-07-08T06:01:38Z")
I add spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.SQLServerDialect to my application.properties and it worked. ---
### Author: ![system](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/system/32/31990_2.png) [@system](https://community.cumulocity.com/u/system) #### Post date: [January 4, 2025, 6:02am UTC](https://community.cumulocity.com/t/jdbc-connection-to-datahub/7696/10 "2025-01-04T06:02:37Z")
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