Andreev reflection: An electron hitting an N-S interface with energy E < Δ cannot enter as a quasiparticle. Instead it retroreflects as a hole (same k, opposite velocity), while a Cooper pair is transmitted into the SC. The hole traces the electron's path backwards.
Josephson current: I = I_c sin(φ) in the ideal case. With transparency T, the BTK formula gives I_c = (eΔ/ℏ)·T/(2−T) at T=0. Andreev bound states at energies ε = ±Δ√(1−T sin²(φ/2)) carry the Josephson current.