The bird species is extremely adaptable, eating fruits, seeds, insects, worms, and even human food. I've seen these birds more than a handful of times at hawker centers near food that hasn't been cleaned up yet (and those get cleaned up fast!).
Actually, the opposite is true. These birds, because of their large numbers, are actually considered pests! The original similar bird, the Common Hill Myna, is now significantly decreasing in numbers as the Javan Myna is more adaptable and taking over the same resources instead. Additionally, the birds have an extremely loud chirp that can actively bother people at night. They also eat local crops, so measures are being taken to reduce the population.