In a large mixing bowl, combine the shredded cabbage, shredded carrots, bean sprouts, green onions, mushrooms, soy sauce, garlic powder, and black pepper. Mix well until all ingredients are evenly coated.
Take one spring roll wrapper and place it on a clean, flat surface with one corner pointing towards you. Spoon about 2 tablespoons of the vegetable mixture onto the wrapper, about 2 inches from the bottom corner.
Fold the bottom corner of the wrapper over the filling, then fold in the sides and roll tightly to form a spring roll. Seal the edge with a little water. Repeat with the remaining wrappers and filling.
Heat about 2 inches of vegetable oil in a deep skillet or pot over medium heat until it reaches 350°F.
Carefully add a few lumpia to the hot oil, frying in batches to avoid overcrowding. Fry for about 3-4 minutes or until golden brown and crispy.
Remove the lumpia with a slotted spoon and drain on paper towels. Serve hot with your favorite dipping sauce.