How to compile and run java programmes in Android terminal -

I am using Terminal IDE on Android to compile and run the .java But I'm not able to do this,

Actually I know how to change the current path in windows ( cd desktop ) if it is on desktop but the terminal IDE About if it is at the root of the SD card.

It supports Java because when I try typing javac then I show the Java version and the app description shows that it compiles Java files

You can check this documentation (out of a while) Terminal IDE -