The R package is available from Bioconductor: https://bioconductor.org/packages/release/bioc/html/BridgeDbR.html
sequenceDiagram
participant User
participant BridgeDbR
participant BridgeDb Java Library
User->>BridgeDbR: loadDatabase()
BridgeDbR->>BridgeDb Java Library: load Derby database
BridgeDb Java Library->>BridgeDbR: IDMapper object
BridgeDbR->>User: IDMapper object