Prior to being composed to a software system, generic components must be configured according to the requirements imposed by the user and the reuse context. Practice shows that most of these configuration operations are invasive in nature. Thus, modular composition alone cannot solve this problem. This paper presents a methodology for invasive configuration of software systems from generic components. Our approach extends type genericity by allowing in addition to type reference fragments general program fragments and metaoperators as configuration parameters. We will introduce our software adaptation tool called Inject/J together with the concepts behind it. The tool serves as an infrastructure for the implementation of our approach. We will also present a case study with some preliminary experiences of the practical application of our approach.