  In this paper, we study the emptiness/nonemptiness and the dimension formulas
of affine Deligne-Lusztig varieties for $Sp_4(L)$. We mainly calculate the
degree of class polynomials for the Iwahori-Hecke algebra of type
$\widetilde{C}_2$. Then, give an explicit description on the
emptiness/nonemptiness and dimension formulas of affine Deligne-Lusztig
varieties for the group $Sp_4(L)$.
