This paper presents a Software Product Line (SPL) extraction approach to handle legacy software systems running on the Java Virtual Machine (JVM), for which the source code is unavailable, and factor in all input programming languages for the JVM. The approach extracts from the bytecode of a collection of software variants created using the Clone-And-Own approach a full SPL with its feature model. We provide a full implementation and integration in the BUT4Reuse framework. An early experiment was carried out on the ArgoUML case study and preliminary results are discussed.