Since there is no populator yet Spring fails when trying to inject since it does not support empty collections. Mark the dependency as optional until we have at least one populator at which point we can simply the code again. Reviewed-on: #122 Reviewed-by: Nico Athanassiadis <nico@dsv.su.se> Co-authored-by: Andreas Svanberg <andreass@dsv.su.se> Co-committed-by: Andreas Svanberg <andreass@dsv.su.se>