It sounds as though your eggplant was attacked by flea beetles. Adult flea beetles are small (about 1/10 inch) black insects that have strong back legs, allowing them to jump like fleas or crickets. To deter the beetles, use floating row covers in spring, right after you plant. Row covers are made from a material that allows light and water to reach your plants but creates a barrier that keeps out insects. Remove the row covers after you see that most flea beetle damage on adjacent plants has stopped and before temperatures get too high in summer. Simply planting your eggplant outdoors a little later than usual in spring can help too. If you wait to plant until most of the beetles have emerged and fed, you will have less of a problem. Luckily, feeding of flea beetles has little effect on fruiting.