<virtualType name="Amazon\Payment\Gateway\ErrorMapper\VirtualErrorMessageMapper"
             type="Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapper">
    <arguments>
        <argument name="messageMapping" xsi:type="object">
            Amazon\Payment\Gateway\ErrorMapper\VirtualMappingData
        </argument>
    </arguments>
</virtualType>

This is a virtual type configuration.

This configuration is for the base area. Base area configurations will apply to all the sub-applications.

This virtualType configuration tells the Object Manager when a user wants a virtual Amazon\Payment\Gateway\ErrorMapper\VirtualErrorMessageMapper object that it should return a Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapper object.

This configuration tells the Object Manager that when a user wants a Amazon\Payment\Gateway\ErrorMapper\VirtualErrorMessageMapper object that the following arguments should be used in the foo object's constructor.

• $messageMapping = new Amazon\Payment\Gateway\ErrorMapper\VirtualMappingData (...)

<type name="Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapper">
    <arguments>
        <argument name="messageMapping" xsi:type="object">
            Magento\Payment\Gateway\ErrorMapper\NullMappingData
        </argument>
    </arguments>
</type>

This is a type configuration.

This configuration is for the base area. Base area configurations will apply to all the sub-applications.

This configuration tells the Object Manager that when a user wants a Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapper object that the following arguments should be used in the foo object's constructor.

• $messageMapping = new Magento\Payment\Gateway\ErrorMapper\NullMappingData (...)

<preference for="Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapperInterface"
            type="Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapper"></preference>

This is a preference configuration.

This configuration is for the base area. Base area configurations will apply to all the sub-applications.

This preference configuration tells the Object Manager when a user wants a Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapperInterface object that it should return a Magento\Payment\Gateway\ErrorMapper\ErrorMessageMapper object.