Recursive fibonacci method import java.awt.*; import java.awt.event.*; import javax.swing.*; public class FibonacciTest extends JApplet implements ActionListener { JLabel numLabel, resultLabel; JTextField num, result; public void init() { Container c = getContentPane(); c.setLayout( new FlowLayout() ); numLabel = new JLabel( "Enter an integer and press Enter" ); c.add( numLabel ); num = new JTextField( 10 ); num.addActionListener( this ); c.add( num ); resultLabel = new JLabel( "Fibonacci value is" ); c.add( resultLabel ); result = new JTextField( 15 ); result.setEditable( false ); c.add( result ); } public void actionPerformed( ActionEvent e ) { long number, fibonacciValue; number = Long.parseLong( num.getText() ); showStatus( "Calculating ..." ); fibonacciValue = fibonacci( number ); showStatus( "Done." ); result.setText( Long.toString( fibonacciValue ) ); } // Recursive definition of method fibonacci public long fibonacci( long n ) { if ( n == 0 || n == 1 ) // base case return n; else return fibonacci( n - 1 ) + fibonacci( n - 2 ); } }