Code:
		
//Create JButton named "NewTree"
JButton NewTree = new JButton("Create a new tree");

	
//Add action Listener
NewTree.addActionListener (new ActionListener()
{
     public void actionPerformed(ActionEvent e)
    {
			 	
			 	
          Object[] options = {"Strings", "Integers"};
	
          int n = JOptionPane.showOptionDialog(null, "Which type of data will you be using in your tree?", "Data Type?", JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, options, options [2]);
			 	
    }
});
Jcreator seems to think that the error seems to be on this this part of the code...

Code:
int n = JOptionPane.showOptionDialog
the error message is...

showOptionDialog(java.awt.Component,java.lang.Object,java.lang.String,int,int,javax.swing.Icon,java.lang.Object[],java.lang.Object) in javax.swing.JOptionPane cannot be applied to (<nulltype>,java.lang.String,java.lang.String,int,int,java.lang.Object[],java.lang.Object)