# Technical¶

What is logged and where can I find it?

Read Server site debugging for detailed information.

What is the config.json file located in the config folder?

This file can be used to define configurations you want to access during the sync progress. They can be access by Application()->getConfig(). A predefined key is developer_logging which has the effect, if it is set to true, that also messages with a DEBUG level are logged.

How can write an abstract mapper?

By using the jtl\Connector\Type\DataType and jtl\Connector\Model\DataModel class an abstract mapper can be implemented. An example on how you get the type of the called mapper can be found in the example connector’s jtl\Connector\Example\Mapper\DataMapper class.

Exceptions has to be caught from within the Endpoint. To make that error public to the JTL-Wawi you have to set an jtl\Connector\Core\Rpc\Error on the jtl\Connector\Result\Action object which is returned.