class JFrame is not recognized

class JFrame is not recognized

I have installed Java SE7 from oracle.com. I am trying to compile the
following program.
import javax.swing.*;
public class app{
public static void main(String args[]){
SwingUtilities.invokeLater(new Runnable() {
public void run(){
JFrame frame=new Jframe("Hello World Swing!");
frame.setSize(500,400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
It gives me the error
app.java:12: error: cannot find symbol JFrame frame=new Jframe("Hello
World Swing!"); ^ symbol: class Jframe 1 error
I have read previous posts and this program is supposed to be standard
material all around. I just can't find the problem. Could anyone please
help me with this?
Thank you