Speed Of Sound Program

I have to write a program that asks the user to enter "air", "water", or "steel", and the distance that a sound wave will travel in the medium. The program should then display the amount of time it will take. The amount of time it takes sound to travel in air can be calculated as follows;

Time = Distance/1,100

The amount of time it takes sound to travel in water can be calculated with the following formula:

Time=Distance/4,900

The amount of time it takes sound to travel in steel can be calculated with the following formula:

Time=Distance/16400

Here is my code:

import java.lang.String;
/**
This program displays numbers padded with leading zeros.
*/
 
public class SpeedofSound {
public static void main(String[] args) {
double D; // declares this as double
D = keyboard.nextDouble();
 const double A = 1100; // declares this as a constant

[Code] .....

The following is the error I'm getting:

----jGRASP exec: javac SpeedofSound.Java
error: Class names, 'SpeedofSound.Java', are only accepted if annotation processing is explicitly requested
1 error
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.