  We study the effect of nonmagnetic impurities in the superconducting state of
the t-J model. The Bogoliubov de Gennes equation is derived using a slave-boson
mean-field approximation, and we solve it numerically at T=0. The
d_{x^2-y^2}-wave order parameter is suppressed near an impurity and its spatial
variation induces the extended s-wave component. We also find the local charge
density wave (CDW)-like feature due to the Friedel oscillations. This leads to
the splitting of the expected zero-energy Andreev bound state. Therefore the
system is unlikely introducing a localized state of other symmetry such as
superconductivity with broken time reversal symmetry or antiferromagnetism.
