  We demonstrate that, quite generally, the spin-singlet even-parity
(spin-triplet odd-parity) pair potential in a superconductor induces the
odd-frequency pairing component with spin-singlet odd-parity (spin-triplet
even-parity) near interfaces. The magnitude of the induced odd-frequency
component is enhanced in the presence of the midgap Andreev resonant state due
to the sign change of the anisotropic pair potential at the interface. The
Josephson effect should therefore occur between odd- and even-frequency
superconductors, contrary to the standard wisdom. A method to probe the
odd-frequency superconductors is proposed.
