If you specifically want the Java Edition (to play on PC servers or use PC mods) on your Android device, you need a launcher. This is the most common method for "Java on Android."

Steps:

Yes – PojavLauncher is legal. However, downloading the Minecraft game files without owning a legitimate license is piracy and against Mojang's terms.

Avoid them. No legitimate, single-APK version exists. Any site offering one is trying to infect your device.