why using command line?

Answer 1

to pass arguments

Answer 2

you can use command line to compile and run Java program to Java class without using any JVM.. don't forget to compile it with Javac...though. is kinda fun . if you know how to compile and run from command prompt.

Answer 3

command lines are the guides lines of a programmer. By using command lines a programmer will able to know whether is he/she going on a right direction or not .