  This work completes the program started in \cite{bb1,bb2,bb3} to derive the
Heisenberg uncertainty relation for relativistic particles. Sharp uncertainty
relations for massive relativistic particles with spin 0 and spin 1 are
derived. The main conclusion is that the uncertainty relations for relativistic
bosons are markedly different from those for relativistic fermions. The
uncertainty relations for bosons are based on the energy density. It is shown
that the uncertainty relations based on the time-component of the four-current,
as was have done in \cite{bb3} for electrons, are untenable because they lead
to contradictions.
