You cannot download a standalone APK of Java Edition Alpha . You can only download the JAR file (Java Archive). To run that JAR on Android, you need an emulation layer.
Websites promising "Full" or "Free" APKs for rare versions of Minecraft often hide significant risks: minecraft java alpha 10 1602 download apk full
Searching for “Alpha 1.0.16 APK full” leads to sketchy sites promising unlocked features. These often contain malware that can: You cannot download a standalone APK of Java Edition Alpha