Use a Joptionpane string input inside a if statement

I'm starting to learn java and I have a trouble with one of my programme. I'm trying to obtain the inductance of an antenna depending on the type of antenna enter by the user. The problem is that I have the dialog box and I enter the input, but after that my code stop and it didn't do the loop. I have been looking over the web and I can't find why my input is not acceptable by the if statement. This is part of my code:

import javax.swing.*; //import javax.swing.JOptionPane;

public class Antenna_Inductance {

public static void main(String[] args) {
    // first we will define all the variable use of the problem set

    // for the lime antenna
   double M;
   int N1;
   int N2;
   double R1;
   double R2;
  // now we can start to programmed the main code 

   String Type= JOptionPane.showInputDialog("Type of Antenna");
    // this is where the code stop and i don't know why

if (Type == "line") {
       String input_rmin= JOptionPane.showInputDialog("Enter minimum distance for r");
        double rmin = Double.parseDouble(input_rmin);
        String input_rmax= JOptionPane.showInputDialog("Enter maximum distance for r");
        double rmax = Double.parseDouble(input_rmax);
       I = 0.01;
       for (r=rmin; r==rmax ;r+=0.05) {

       B_line = (mu*I)/(2*pi*r);

    System.out.println("Inductance for line antenna =" + B_line);
       }

So, i could really use some help on this one. Thank you and have a nice day