MySQL Connector/J 6.0.5 m4 Development Release has been released

Dear MySQL users,

MySQL Connector/J 6.0.5 m4 Development Release is a developer milestone
release for the 6.0.x series.
This release includes the following new features and changes, also described
in more detail on

As always, we recommend that you check the “CHANGES” file in the download
archive to be aware of changes in behavior that might affect your application.

To download MySQL Connector/J 6.0.5 M4, see the “Development
Releases” tab at


Changes in MySQL Connector/J 6.0.5 (2016-10-19, Milestone 4)

Version 6.0.5 Milestone is the forth development release of
the 6.0 branch of MySQL Connector/J, providing an insight
into upcoming features. It is suitable for use with MySQL
server versions 5.5, 5.6, and 5.7. It supports the Java
Database Connectivity (JDBC) 4.2 API.

Functionality Added or Changed

* Added support for the error codes of two MySQL server
rver.html#error_er_xa_rbtimeout) and ER_XA_RBDEADLOCK
rver.html#error_er_xa_rbdeadlock). (Bug #13702433, Bug

* X DevAPI: Client-side failover is now supported. It is
enabled by specifying multiple hosts in the X DevAPI
connection URL. See X DevAPI URL Format for more details.

* com.mysql.cj.core.MysqlType can now be used as
java.sql.SQLType in JDBC methods.

* X DevAPI: A new method, createTable(), has been added to
the Schema interface. See MySQL Connector/J X DevAPI
Reference ( for

* X DevAPI: A new method, bindToDefaultShard(), has been
added to the XSession interface. It creates a “virtual”
NodeSession instance, which shares the connection to the
router with the XSession that was used to create it. See
MySQL Connector/J X DevAPI Reference
( for details.

* X DevAPI: For any function that takes a value list of
parameters for its argument, there is now more
flexibility with how the parameters are to be specified:
they can now be supplied either as a value list or a list
of individual parameters.

* The Extension interface has been removed. Extension
classes now implement their own interfaces.

Bugs Fixed

* In certain cases, the exception interceptor was being
triggered twice in the internal SQLException factory
method. Also, if the exception interceptor returned an
exception with the cause already initialized, the same
factory method would fail to initialize the cause again,
and the real cause for the exception remained uncaptured.
(Bug #23743956)

* getLength() returned -1 for fields of the LONGBLOBL,
LONGTEXT, and GEOMETRY data types. This is due to the way
these data types are handled by protocol buffers, and
this fix makes the method return the right values. (Bug

* A memory leakage occurred when the connection properties
cachePrepStmts and useServerPrepStmts were both set to be
true and server-side prepared statements were set as
non-poolable, which resulted in the prepared statement
being not closable by the client, and the number of
prepared statements then kept on increasing.
When the memory leakage described above occurred, it did
not make Connector/J fail, as Connector/J switched to
using client-side prepared statements when the maximum
number of prepared statements was reached. However, when
rewriteBatchedStatements was also set to true, the switch
to client-side prepared statements did not occur, and
Connector/J threw the MySQLSyntaxErrorException (“Can’t
create more than max_prepared_stmt_count statements”)
when the client wanted to create more prepared statements
than allowed.
This fix corrected the way prepared statements are
handled in order to avoid both of the problems described
above. (Bug #22954007, Bug #80615)

* ResultSet.getString() sometimes returned garbled data for
columns of the JSON data type. This was because JSON data
was binary encoded by MySQL using the utf8mb4 character
set, but decoded by Connector/J using the ISO-8859-1
character set. This patch fixes the decoding for JSON
data. Thanks to Dong Song Ling for contributing to the
fix. (Bug #22891845, Bug #80631)

* When Connector/J retrieved the value of a BIT column as a
string using, for example, getString(), it returned the
wrong string if the BIT value happened to be equivalent
to the decimal value of some ASCII character. This was
because Connector/J treated the BIT value as a character
code; thus, for example, the value “01100001” (decimal 97
in binary) was interpreted as the character “a” (whose
ASCII value in decimal is 97), which was returned by the
function. This fix corrected the parsing behavior of
Connector/J on BIT values, so that a string
representation of the number (“97” in the last example)
is returned by getString(). (Bug #21938551, Bug #78685)

* When the connection property useLocalTransactionState was
set to “true” and autocommit was set to “false” on the
server, if any exception was thrown, any further calls
for rollback() or commit() were not sent to the server.
It was because when there was an exception while
executing a query, Connector/J lost the information
regarding the server’s transaction state. This patch
fixes this issue by preserving the previous transaction
state for the current connection when any exception is
thrown. (Bug #20212882, Bug #75209)

* An invalid connection URL caused Connector/J to throw a
NullPointerException. With this fix, an SQLException is
thrown instead in the situation. (Bug #18759269, Bug

* When a very large amount of compressed data is
transmitted from the server to the client and under very
special circumstances, a CommunicationsException might
occur. It happened when a single compressed packet from
the server was not big enough to provide an entire
uncompressed packet to the client side. With this fix,
Connector/J reads as many compressed packets as necessary
to fill the size of the uncompressed packet that was
being requested. Thanks to Ryosuke Yamazaki for
contributing to the fix. (Bug #11756431, Bug #48346)


Reporting Bugs
We welcome and appreciate your feedback and bug reports:

On behalf of the MySQL Release Team
-Sreedhar S