  Through full solvability of 2+1 dimensional general relativity we derive out
exact dynamic inner metric of collapsing stars with inhomogeneous initial mass
distribution but joining with outside Anti-deSitt-Schwarzschild black holes
smoothly. We prove analytically by standard quantum mechanics that the
log-number of such solutions, or microscopic states of the system is
proportional to the perimeter of the outside black holes. Key formulas for
generalizing to 3+1D Schwarzschild black holes are also presented. Our result
provides a bulk space viewpoint to questions on what the microscopic degrees of
freedom are and who their carriers are in various holographic and/or asymptotic
symmetry methods to black hole entropies. It may also shed light for
singularity theorem and cosmic censorship related researches.
