Java APIs

I am trying to do a search on names inwhich i input into a file and then show them on a joptionpane. My problem is that I can't get it to run b/c it says that i have incompatable types. Please help if at all possible.

String name, custid, num, result;
int id, element;


public void search(){

num = JOptionPane.showInputDialog("Enter Customer ID:");
id = Integer.parseInt(num);
name = tree.lookUp(id);
result = JOptionPane.showMessageDialog(null,new JTextArea(name));

}