Dynamic injection is not possible indeed, you need to have setters/getters for each of of the values you define. This is not possible for the moment, using plain field-injection. A solution can be to use a JSON-structure (or whatever format you like) as value of the <activiti:string> element, containing the key/value combinations. Use Jackson or whatever JSON parser you want in the delegate listener to get a Map from the JSON-structure, defined in the BPMN.