The VM that runs Linux is not implemented in Java. It uses a variant of KVM called pKVM. (pKVM allows for mutually distrusted execution environments: https://source.android.com/docs/core/virtualization/security.)

Debian code won't converted into Java bytecode, though, so it won't run on the JVM. If it's the ARM version, it'll probably just run directly on the CPU.

Uh, this is wrong on different levels.

The java bytecode gets translated to a different virtual machine, dalvik/dex (iirc) so no jvm involved.

Other than that, afaik, there’s also a native development kit if you need to call into native code (c/c++/whatever).