  We present a two-dimensional photonic crystal design with a microcavity of
four defect dielectric rods with eigenfrequencies residing in the propagating
band of directional waveguide. In the linear case for tuning of material
parameters of defect rods the nonrobust bound state in the continuum (BSC)
might occur. The BSC is a result of full destructive interference of resonant
monopole and quadrupole modes with the same parity. % to trap light interior of
the microcavity. A robust BSC arises in a self-adaptive way without necessity
to tune the parameters of the microcavity with the Kerr effect. Lack of the
superposition principle in nonlinear systems gives rise to coupling of the BSC
with injecting light. That forms a peculiar shape of isolated transmittance
resonance around BSC frequency. We show if injecting light is switched off the
BSC storages light that opens a way for light accumulation.
