java - Classes in the same package not communicating with each other -

i started working on snake game, , made main class, , made display class immediately. created package, "game" them, when compile main class, console says can't find "display."

here main class:

package game;  public class main { public static display f = new display();  public static int w = 700; public static int h = 400;  public static void main( string[] args ) {     f.settitle("  snake");     f.setsize(w, h); } // end of method main() } // end of class main 

here display class (not completed):

package game;  import javax.swing.*;  public class display extends jframe { public display() {  } // end of constructor } // end of class display 

consider directory structure :

                 project                     |          -------------------------          |                       |        source          |                      build (this compiled stuff go or resources)     ------------     |          | main.java    display.java 

now command prompt, go project directory , write :

javac -d build source\*.java 

this create package folders inside build folder automatically (in case game folder created automatically containing display.class , main.class). go build folder , run :

java game.main 

more information regarding use of javac can found, typing javac on terminal. options javac can used with, displayed on terminal.