Missing return statement
<p>I am getting the following errors in my code: 
-Missing return statement
-Cannto find symbol in the second method</p>

<p>Here is my code:</p>

<pre><code>import java.io.*;
import javax.swing.JOptionPane;

public class Converter {
    public static void main(String[] args) throws Exception{
        //BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String unit = JOptionPane.showInputDialog("Enter unit F or C: ");

        String temp1 = JOptionPane.showInputDialog("Enter the Temperature: ");


        double temp = Double.valueOf(temp1).doubleValue();
    }




        public static double convertTemp(){
         if((unit.equals("F"))||(unit.equals("f"))){
        double c= (temp - 32) / 1.8;
        JOptionPane.showMessageDialog(null,c+" Celsius"));
        }

         else if((unit.equals("C"))||(unit.equals("c"))){
        double f=((9.0 / 5.0) * temp) + 32.0;
        JOptionPane.showMessageDialog(null,f+" Fahrenheit");

}
}
}
</code></pre>
