https://www.zkteco.com/en/product_detail/ZKFinger-SDK-Android.html
Mamasodikov/ZKFinger-SDK_Android
ZKFinger SDK Android can provide support for ZKTeco fingerprint scanners. Its compatible devices are SLK20R and ZK series fingerprint scanners, including ZK9500, ZK6500, ZK8500R. The SDK could be work on Android OS. Users could develop app to get fingerprint image/template. There are development interfaces development documents and Demo inside SDK,
Java