Hello,
If this JAR is avaiblable thru Maven you can use this procedure: Docker | Simplicité Documentation
Note that this procedure will preserve all indirect dependencies already present in Simplicité which may result on on unexpected behaviors when using the JAR
Note also that if this JAR is a “fat bundle” it might cause unexpected behaviors on Simplicité (as it can hide an existing dependencies of the platform)
Can you tell us what is this JAR you want to add so as we make a analysis of the potential conflicts ?