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MySQL Connector/J 5.1.39 has been released

I’m pleased to announce that MySQL Connector/J 5.1.39 Maintenance Release is now generally available.

MySQL Connector/J can be downloaded from the official distribution channels MySQL Downloads and The Central Repository. The commercially licensed version is available for download at My Oracle Support.

As always, we recommend that you check the CHANGES file in the download archive and/or the release notes page to know what is new and if there are any changes that might affect your applications.

With MySQL Connector/J 5.1.39 you get the continuously improved JDBC driver for MySQL databases, now including several fixes and upgrades. Even if you didn’t face any of the fixed issues, we do recommend that you upgrade to the latest version.

I’d like to highlight the most relevant fixes and improvements in this release:

MySQL Fabric support related issues

As you well know by now, MySQL Fabric support in Connector/J is built on its generic multi-host connections feature, more specifically on replication connections. This feature, along with load-balanced connections support, have received several improvements all over the latest releases. This time, we fixed and tuned up a few incoherences that were spotted on a few corner cases, namely when, due to the Fabric management process, the list of known hosts in an active connection could actually become empty for a short period of time while performing the fail-over, and so causing a whole set of new problems. As a consequence of these developments, we introduced a new connection property:

loadBalanceHostRemovalGracePeriod. This property sets the time, in milliseconds, that the driver should wait for a load-balanced connection to be allowed to switch to a different host when the currently active one is being removed, either by an internal process such as in a Fabric or a replication connection, or by dynamic hosts management, through the JMX interfaces the driver provides. Default value is 15000 milliseconds.


Additional improvements and fixes

  • Unnecessary exception throwing and capturing when establishing connections.
  • Temporal data corruption in prepared statements under special circumstances.
  • Incorrect JDBC 4.2 Java 8 Time support when using cached prepared statements.
  • Application server using multiple class loaders could face a NullPointerException when setting up the driver’s time zone configurations.
  • Exception caused by missing metadata information in updatable result sets.
  • Concurrent modification issue on closing statements and connections concurrently from different threads.
  • Maintenance fixes in the test suite.
  • Source code formatting, Copyright notice fixes.
  • Build script adjustments, new code coverage reports, compiler warnings cleanup.
  • Manifest fixed to expose Fabric connections.
  • Support for latest changes in MySQL protocol, introduced in MySQL 5.7, namely the deprecation of EOF packets.


Enjoy this new release of Connector/J and stay tuned for the next releases as there is still much to deliver.

Get the most out of this Connector/J release by reading its official documentation or by getting the developer’s support directly from the forum channel.

Thank you all for your support and keep in touch!

On behalf of the MySQL Connector/J Team