  It is demonstrated that in the diffusive
superconductor-ferromagnet-superconductor (S/F/S) junctions the current-phase
relation is practically sinusoidal everywhere except in a narrow region near
the 0-Pi transition. In this region the second harmonic dominates the scenario
of the 0-Pi transition. We predict a first order transition for the S/F/S
junctions with a homogeneous F barrier. However, in real junctions a small
modulation of the thickness of the barrier may favor the continious 0-Pi
transition and the realisation of the Josephson junction with an arbitrary
ground state phase difference. The performed calculations of the second
harmonic amplitude provide a natural explanation of the recent contradictory
results on the second harmonic measurements.
