Additional info that might help...

If I start the server and the first access to the remote server is via ApacheInterface, this is the error message I get:

Error Code: 1296. Got error 174 'Connecting: java.lang.NoClassDefFoundError: org/apache/commons/dbcp2/BasicDataSource rc=0' from CONNECT

However if I first access the remote server via JdbcInterface (which works correctly) then try the ApacheInterface I get this error message:

Error Code: 1296. Got error 174 'Connecting: java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.dbcp2.BasicDataSource rc=0' from CONNECT

Please let me know if there is any additional info I can provide.

Thank you.

I cannot reproduce it on Windows. I start the session by:

set global connect_class_path='postgresql-9.4.1208.jar;E:/Oracle/ojdbc6.jar;E:/Apache/commons-dbcp2-2.1.1/commons-dbcp2-2.1.1.jar;E:/Apache/commons-pool2-2.4.2/commons-pool2-2.4.2.jar;E:/Apache/commons-logging-1.2/commons-logging-1.2.jar;D:/mysql-connector-java-6.0.2/mysql-connector-java-6.0.2-bin.jar;D:/MariaDB-connector-java-1.4.6/mariadb-java-client-1.4.6.jar';

set global time_zone = '+2:00';

set connect_java_wrapper='ApacheInterface';

Then access some pre-defined tables:

select * from jdrv;

or:

CREATE TABLE jboys

ENGINE=CONNECT CONNECTION='jdbc:mysql://localhost/connect?user=root&useSSL=false' `TABLE_TYPE`='JDBC' `TABNAME`='boys' `OPTION_LIST`='scrollable=1';

select * from jboys;

To morrow I'll try it on Linux ubuntu

I was not aware that the commons-logging was required. I had commons-dbcp2 and commons-pool2 but not the commons-logging... and the tell tale class name was cut off in the error message. Once I added commons-logging to the classpath it worked perfectly

Unless I missed it, maybe you can update the documentation to state that ApacheInterface needs 3 libs:
commons-dbcp2
commons-pool2
commons-logging

Also, how do I configure the connection pool without writing a custom ApacheInterface class?

On to stress testing, then onto pilot testing. Zero crashes so far (very unlike the ODBC experience where a bad driver interactions could take down the entire MariaDB server - has not happened once yet with JDBC... just a nice mostly clean error message).

how do I configure the connection pool without writing a custom ApacheInterface class?
Good question. The current Apache wrapper is very basic and provides nothing for further configuration. Configure parameters are listed in:
http://commons.apache.org/proper/commons-dbcp/configuration.html
but I did not find examples showing how to implement them (the links to samples are broken)
Any suggestion or help is warmly welcome!

looking at the 2.1.1 BasicDataSource api docs:

Basic implementation of javax.sql.DataSource that is configured via JavaBeans properties. This is not the only way to combine the commons-dbcp and commons-pool packages, but provides a "one stop shopping" solution for basic requirements.

public void setConnectionProperties(String connectionProperties)

Sets the connection properties passed to driver.connect(...). Format of the string must be [propertyName=property;]* NOTE - The "user" and "password" properties will be added explicitly, so they do not need to be included here.

Parameters:

connectionProperties - the connection properties used to create new connections

I'm not sure but maybe this is the answer?

From what I understand setConnectionProperties is not used to configure the basicDataSource itself but to send property settings to the driver used by the connection. I have tried a test by enabling settings connection properties via a new create option, for example:

CREATE TABLE jboys

ENGINE=CONNECT  TABLE_TYPE=JDBC TABNAME='boys' 

CONNECTION='jdbc:mysql://localhost/connect?user=root'

OPTION_LIST='properties=maxRows=5;useSSL=false';

The property list (here maxRows=5;useSSL=false) is passed to the ApacheInterface as a fifth parameter and when it is not null, is used as the parameter of setConnectionProperties that send them to the MySQL driver.
I checked in debug mode that it is indeed executed and it works.
Does this answer your question and should I implement it?
However, it might be useless because it is simpler to do:

CREATE TABLE jboys

ENGINE=CONNECT TABLE_TYPE=JDBC TABNAME='boys'

CONNECTION='jdbc:mysql://localhost/connect?user=root&maxRows=5&useSSL=false';

Unlike the first solution, this one works as well with the Apache or MySQL wrappers.

I agree, don't implement as its redundant.
I think this ticket can be closed as the ApacheInterface error just requires a tweak to the documentation as noted above. Anything else I come across I'll open as a different ticket.
Thank you!

I have updated the documentation to indicate precisely what jar files are needed when using the Apache interface.