  The linear natural and forced oscillations of a hemispherical bubble on a
solid substrate are under theoretical consideration. The contact line dynamics
is taken into account with the Hocking condition, which eventually leads to
interaction of the shape and volume oscillations. Resonant phenomena, mostly
pronounced for the bubble with the fixed contact line or with the fixed contact
angle, are found out. The limiting case of weakly compressible bubble is
studied. The general criterion identifying whether the compressibility of a
bubble can be neglected is obtained.
