Ejemplos Java

Hola mundo

En python:

print "Hello World!"

En java:

public class Hello {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

Ejemplo con swing

import javax.swing.*;
 
public class TempConvGUI {
 
    public static void main(String[] args) {
        String fahrString;
        Double fahr, cel;
 
        fahrString = JOptionPane.showInputDialog("Enter the temperature in F");
        fahr = new Double(fahrString);
        cel = (fahr - 32) * 5.0/9.0;
 
        JOptionPane.showMessageDialog(null,"The temperature in C is, " + cel);
    }
}