Yes, GLFW is not involved at all. The window is managed by JavaFX. DriftFX provides a node (DriftFXSurface) that you can add to a JavaFX scene, with an associated OpenGL context and a “framebuffer” texture. The context is supposed to integrate with the JavaFX rendering backend (even Direct3D on Windows), copying the framebuffer to JavaFX without leaving the GPU.
That sounds like exactly what I need. hah. Fingers crossed