I have found equation for moment of inertia $(J)$. I'm calculating $J$ for hemisphere, with rotational axis $Z$.
$$ J = \iiint\limits_V r^2 \cdot \rho \cdot dV $$
But if $\rho$ is constant (homogenous), I can do: $$ J = \rho \cdot \iiint\limits_V r^2 \cdot dV $$
Which is: $$ J = \rho \cdot V $$ $$ J = m $$
Am I right?