  Motivated by the recent experimentally observed manifestations of the quantum
critical point fluctuations in the thermodynamic properties of multiband
superconductors, we derive a general expression for the Josephson current of
various junctions between two superconductors in the phase of superconductivity
coexistence with the spin-density-wave. We demonstrate that the critical
current peaks at the quantum critical point that separates pure and mixed
superconducting phases. We argue that our results are generic and, in
particular, can be adopted to explain the recent observations of a nonmonotonic
dependence of the supercurrent on the external pressure in the heavy fermion
superconductor CeRhIn$_5$, and on the chemical doping in iron-based
superconductors such as Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$.
