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Proper setting of application properties for "No operation allowed connection" exception

Application: Java spring boot + mysql
Story:
application log showed "Could not open JDBC Connecton for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure"
Recovery of the DB instance has been triggered since hardware problem occurred in RDS instance
After 10 mins, the recovery is done.
application log showed "Could not commit JDBC transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed." instead of previous exception.
After 45 mins, application resumed normal without manual operations.
Questions:
Will restarting the application solve the problem instantly?
Manual operation might not be the best to resolve such problem. But if I want it be auto resumed shortly, anything I can do to the setting datasource properties? i.e. set spring.datasource.justswap.time-between-eviction-runs-millis shorter?
Current datasource setting:
spring.datasource.xxx.maxActive=700
spring.datasource.xxx.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.xxx.test-on-borrow=false
spring.datasource.xxx.test-while-idle=true
spring.datasource.xxx.time-between-eviction-runs-millis=3600000
spring.datasource.druid.stat-view-servlet.enabled=false

Issue integrating mariaDB client with MySQL DB

I am running a java application with MySQL as the DB server. DB is a AWS RDS. The MySQL connector is published under GNU/GPL so it has to be substituted with something more lenient. Maria DB client claimed to be compatible. But ever since MariaDB client is being used we are seeing the below intermittent issue during DB intensive activities:
Excption:-
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/Projectname] threw exception [Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection] with root cause
java.sql.SQLNonTransientConnectionException: (conn=1530488) Connection is closed
at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73)
at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.create(ExceptionFactory.java:187)
at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.cmdPrologue(AbstractQueryProtocol.java:1940)
Caused by: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113)
Caused by: java.sql.SQLNonTransientConnectionException: Could not connect to address=(host=XXXXXXXXXX)(port=3306)(type=master) : (conn=1530487) could not load system variables
at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73)
at org.mariadb.jdbc.internal.util.exceptions.ExceptionFactory.create(ExceptionFactory.java:192)
at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1372)
I have tried increasing the time_wait and max_allowed_packet to the maximum allowed but the issue still exists.
Versions:-
MySQL - 5.7.26
MariaDB connector - 2.6.2

Just came across this, found an answer. On my side this was for an Aurora 1 MySQL DB (equiv to 5.6).
As per Diego Dupin in https://jira.mariadb.org/browse/CONJ-824:
only good solution is to use option `usePipelineAuth=false&useBatchMultiSend=false`
So your DB connection string might look like this:
jdbc:mysql://127.0.0.1:3307/mydbname?usePipelineAuth=false&useBatchMultiSend=false
More details:
Aurora proxy has a known race condition issue that results in skipping other
queries in proxy buffer. connection might be in hang waiting for query response.
During authentication, socket has a timeout, that will result throwing the error
you describe.
So if `usePipelineAuth` or `useBatchMultiSend` is enable, it might work ... or not.
All pipeline options (`usePipelineAuth` and `useBatchMultiSend`) must be disabled when using aurora.
Problem has been reported to aurora a few times without correction.

Java application deploying on Linux platform

I am trying to deploy project war file on Linux platform and its giving me following error.
com.microsoft.sqlserver.jdbc.SQLServerException: This driver is not configured for integrated authentication. ClientConnectionId:1207f4ed-32d0-44e8-ae1c-308b157e9903
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is org.hibernate.exception.JDBCConnectionException: Could not open connection
Server details
Server - Tomcat v8.5
configuration in the property file.
jdbc.url = jdbc:sqlserver://DC01ODSDBDV03;databaseName=ExecDB_Stg;integratedSecurity=true;
hibernate.dialect = org.hibernate.dialect.SQLServer2008Dialect
hibernate.show_sql = true
hibernate.format_sql = true
We have tried adding the following javakerberos property but it didnt work.
authenticationScheme=JavaKerberos
Please help.

To save you a lot of pain really try to convince sql admins to allow you the password authentication.
Otherwise you need to run Tomcat under an AD service account, which is not difficult if you kow how to do that.
I wrote a blog about SPNEGO authentication. you do not need all the steps, it is enough that Tomcat will run as AD service. (until configuring krb5.ini file)

Oracle socket read time out error in Spring boot application

I have created a spring boot application. When I put load on the application after sometime load on database server started increasing and I got started socket read time out error.
2016-10-24 21:56:10 [pool-3-thread-296] ERROR o.h.e.jdbc.spi.SqlExceptionHelper - IO Error: Socket read timed out
2016-10-24 21:56:10 [pool-3-thread-296] ERROR
Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Could not open connection
Here is the properties file details of Springboot application
spring.datasource.url=jdbc:oracle:thin:#<ip>:1521:<dbname>
spring.datasource.driver-class-name=oracle.jdbc.OracleDriver
spring.datasource.initial-size=100
spring.datasource.maxActive=1500
spring.datasource.validationQuery=select 1 from dual
spring.jpa.hibernate.dialect = org.hibernate.dialect.Oracle10gDialect
spring.jpa.show-sql = true
spring.jpa.hibernate.naming_strategy=org.hibernate.cfg.EJB3NamingStrategy
spring.datasource.pool-prepared-statements=true
spring.datasource.pool-prepared-statements-cache-size=500
spring.datasource.max-open-prepared-statements=500
Since the error is very generic , I am not able to figure out why I am getting socket read timeout exception.
I also need to know what does "[pool-3-thread-296]" mean in exception log ?

Have you tried this? This worked for me
https://springframework.guru/configuring-spring-boot-for-oracle/

Mysql communication error in tomcat even with out using any mysql in application

I am Getting following error when ever i am starting my tomcat
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.ConnectException
MESSAGE: Connection refused
I am getting this error even with out using any application in my tomcat.
Could you please help me why tomcat is looking for mysql connect at the time of start
Regards

May be you have configured a Tomcat Datasource Resource in your server.xml or context.xml in your ${CATALINA_BASE}/conf directory. So, whenever tomcat starts it tries to create the connection pool for your datasource and it is not able to communicate to the db server host. This is highly possible if you don't use mysql in your application