how to compile java program in command prompt

Answer 1

javac filename.java to compile the program & then
java filename to execute the program!

Answer 2

write javac program name with .java extension and then press enter

Answer 3

go with this app

Answer 4

Solved it :

using your command prompt
navigate to the directory where your program is , if for instance your program is named Demo.java ,
type javac Demo.java then hit enter.
watch as your program compiles .