cf. title of the question, is there a Java API to make Cardano developers ?
1Welcome to our community! I recommend you add more detail to your question, simply because it's very unusual for the question body to just be a repeat of the question title. Perhaps you could say a bit about your overall goals with such an API or the motivation for why want this, or if you prefer open-source vs proprietary, etc.– Nike DattaniJun 23, 2021 at 21:05
Yes, try cardano-client-lib SDK written in Java.