How to fix "com.mysql.cj.jdbc.exceptions.CommunicationsException" error

Question

I moved my app to my production server and I am getting this error. I think it might have to do with my Amazon RDS configuration but I'm not sure. I configured it to work correctly with my development app. The only thing different is that I moved it to Windows Server 2012 R2.

I tried changing the mysqlconnector jar several times. I included the latest jar. I also include the mysqlconnector dependency in my pom.xml.

Here is my application.prod.properties:

spring.profiles.active=prod
spring.datasource.url=jdbc:mysql://databaselink:port/dbname?useSSL=false
spring.datasource.username=username
spring.datasource.password=password
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform:org.hibernate.dialect.MySQL5Dialect
spring.mvc.view.prefix=/WEB-INF/views/
spring.mvc.view.suffix=.jsp
spring.jpa.hibernate.ddl-auto: update
spring.jpa.show-sql=true
aws.sns.topic.volvoservice.ARN=xxxxx
aws.temporary.credentials.validity.duration=7200
aws.access.key.id = 
aws.access.key.secret = 
aws.region=us-east-1
server.port=9080
#Expose HTTP REST ENDPOINTS
management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=when-authorized
management.endpoint.health.roles=ADMIN

I want to be able to run my application on the production server. Any help would be appreciated. Thanks!

Here is some of the error:

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117) ~[HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123) ~[HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365) ~[HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194) ~[HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:460) [HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:534) [HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) [HikariCP-2.7.9.jar!/:na]
    at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) [HikariCP-2.7.9.jar!/:na]
    at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:151) [spring-jdbc-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:115) [spring-jdbc-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:78) [spring-jdbc-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:319) [spring-jdbc-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:356) [spring-jdbc-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.boot.autoconfigure.orm.jpa.DatabaseLookup.getDatabase(DatabaseLookup.java:72) [spring-boot-autoconfigure-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.autoconfigure.orm.jpa.JpaProperties.determineDatabase(JpaProperties.java:166) [spring-boot-autoconfigure-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.jpaVendorAdapter(JpaBaseConfiguration.java:111) [spring-boot-autoconfigure-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaConfiguration$$EnhancerBySpringCGLIB$$be7f834.CGLIB$jpaVendorAdapter$6(<generated>) [spring-boot-autoconfigure-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaConfiguration$$EnhancerBySpringCGLIB$$be7f834$$FastClassBySpringCGLIB$$25526138.invoke(<generated>) [spring-boot-autoconfigure-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) [spring-core-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:365) [spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaConfiguration$$EnhancerBySpringCGLIB$$be7f834.jpaVendorAdapter(<generated>) [spring-boot-autoconfigure-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_191]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_191]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_191]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_191]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:582) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1096) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:535) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:818) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:724) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:474) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1096) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:535) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:818) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:724) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:474) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1096) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:535) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) [spring-beans-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1089) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:859) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.9.RELEASE.jar!/:5.0.9.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) ~[spring-boot-2.0.5.RELEASE.jar!/:2.0.5.RELEASE]
    at com.principleauto.rfid.RfidRestApiApplication.main(RfidRestApiApplication.java:12) ~[classes!/:1.0]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_191]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_191]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_191]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_191]
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) ~[com.principleauto-1.0.jar:1.0]
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) ~[com.principleauto-1.0.jar:1.0]
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) ~[com.principleauto-1.0.jar:1.0]
    at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) ~[com.principleauto-1.0.jar:1.0]
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_191]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191]
    at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:91) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.NativeSession.connect(NativeSession.java:152) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    ... 84 common frames omitted
Caused by: java.net.ConnectException: Connection timed out: connect
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_191]
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source) ~[na:1.8.0_191]
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source) ~[na:1.8.0_191]
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source) ~[na:1.8.0_191]
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source) ~[na:1.8.0_191]
    at java.net.PlainSocketImpl.connect(Unknown Source) ~[na:1.8.0_191]
    at java.net.SocksSocketImpl.connect(Unknown Source) ~[na:1.8.0_191]
    at java.net.Socket.connect(Unknown Source) ~[na:1.8.0_191]
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65) ~[mysql-connector-java-8.0.13.jar!/:8.0.13]
    ... 87 common frames omitted

2019-01-11 09:13:15.946  WARN 4776 --- [main] o.s.b.a.orm.jpa.DatabaseLookup           : Unable to determine jdbc url from datasource

What happens if you try to connect to that same MySQL instance with a typical desktop client from the same machine where your Java program runs? If it doesn't connect at all, you probably haven't rigged your AWS firewall settings to let port 3306 pass through. What line of code in your Java program generates the exception. Please [edit] your question to tell us. — O. Jones, Jan 10 '19 at 23:17
`CommunicationsException` is rather non-descriptive. Please show full exception, with full stacktrace. — Andreas, Jan 10 '19 at 23:35
Added some of stacktrace. @O.Jones How do I rig AWS firewall settings? — Roro, Jan 11 '19 at 15:21
AWS security settings lie beyond the scope of SO answers. Search for something like "how do I connect to AWS RDS from a java app on my laptop computer". — O. Jones, Jan 11 '19 at 15:36
Added an inbound rule for the ip in the AWS security group for the DB. Still getting the same error.... — Roro, Jan 11 '19 at 16:03

score 2 · Answer 1 · answered Feb 05 '19 at 19:28

From the client instance, try doing a telnet on the DB port to test if all your security group settings are applied correctly.

telnet endpoint 3306

If the connection does go through, then the issue is with your client code. Cross check that you have wired the right endpoint in your code.

If the telnet connection does not group (I'm guessing that it would not), then it is guaranteed that your security group settings are not set correctly. In order to debug this further, we would need more details on:

The list of vpc security groups associated with your cluster.
The details of each of these vpc security groups

It works on every system except my clients.... he has a new install of centos 7. i am able to telnet to the database(external). any idea of why this wont work? i am using the latest version of the jdbc. i even added it as a dependency in my pom file. — Jp Silver, Jan 28 '21 at 09:42

How to fix "com.mysql.cj.jdbc.exceptions.CommunicationsException" error

1 Answers1