gistfile1.java

public static Field SetArmorModel_stack;

public static void setStack(SetArmorModel event, ItemStack stack) {
    if (SetArmorModel_stack == null) {
        SetArmorModel_stack = SetArmorModel.class.getField("stack");
        SetArmorModel_stack.setAccessible(true);
    }
    SetArmorModel_stack.set(event, stack);
}