String issue, and if- statement won't work - Java

Question

If I use this code, and the textfile with the right text:

package me.ruban.AccountManager;

import java.io.File;
import java.io.IOException;
import java.util.Scanner;`

public class Login {

private String readNickname;
private String readPassword;
private String inputNickname;
private String inputPassword;
private static String[] accountDetails;
private static String line;

private boolean exists = true;
private boolean login = false;

public Login(String inputNickname, String inputPassword) throws IOException {
    this.inputNickname = inputNickname;
    this.inputPassword = inputPassword;

    if(new File(inputNickname + ".acc").exists() == false) {
        System.out.println("[Login] This account does not exists!");
        exists = false;
    }

    if(!exists == false) {
         try {
                Scanner input = new Scanner(new File(inputNickname + ".acc"));

                line = "";
                while (input.hasNextLine()) {
                    System.out.println("[Login] Reading...");
                    line += input.nextLine() + " ";
                }
                input.close();
                System.out.println("[Login] Loaded " + inputNickname + ".acc succesfully.");

            } catch (Exception e) {
                e.printStackTrace();
            }

         accountDetails = line.split(" ");

         if(accountDetails[0] == inputNickname) {
             if(accountDetails[1] == inputPassword) {
                 login = true;
                 System.out.println("[Login] Login is aviable!");
             }
         }
    }
}

public boolean getLogin() {
    return login;
}

public boolean getExists() {
    return exists;  
}

public String getLine() {
    return line;
}

public static void main(String[]args) throws IOException {
    Login l = new Login("username", "password");
    System.out.println();
    System.out.println(accountDetails[0]);
    System.out.println(accountDetails[1]);
    System.out.println();
    System.out.println(l.getLogin());
}

}

My output will be:

[Login] Reading...
[Login] Reading...
[Login] Loaded username.acc succesfully.

username
password

false

This is not what I wan't, because the false should be true according to my code and my textfile. So my question is: how to get the false to true.

Thanks