~cpp 
import javax.swing.*;

public class HelloWorld {
	
	private String sentence;
	
	public HelloWorld()
	{
		
	}

	public HelloWorld(String temp)
	{
		sentence = temp;		
	}
	
	
	public void setSentence(String temp)
	{
		sentence = temp;		
	}
	
	public void Say()
	{
		JOptionPane.showMessageDialog(null, sentence);
	}
	
	
}

~cpp 

public class TestHello {
	public static void main(String args [])
	{
		HelloWorld h = new HelloWorld();
		h.setSentence("Hello World!");
		h.Say();
		
		HelloWorld h2 = new HelloWorld();
		System.exit(0);
		
	}
}