title: Java SQL Check if username already exists
body: <p>I am trying to check if the username already exists in the table:
  The database also has the field set to unique
  The method will return a boolean stating if the username already exists or not.
  The part of my code that sets the usernameExists var to true never runs even if the usernames are the same.</p>
  
  <pre><code> public static boolean CheckUsernameExists(String username)
  {
      boolean usernameExists = false;
  
      try
      {
  
          Class.forName("com.mysql.jdbc.Driver");
          Connection connection = DriverManager.getConnection(urlDB, usernameDB, passwordDB);
  
          PreparedStatement st = connection.prepareStatement("select * from Members order by username desc");
          ResultSet r1=st.executeQuery();
          String usernameCounter;
           if(r1.next()) 
           {
             usernameCounter =  r1.getString("username");
             if(usernameCounter == username) //this part does not happen even if it should
             {
                 System.out.println("It already exists");
                usernameExists = true;
             }
           }
  
  
       }
  
       catch (SQLException e) 
       {
          System.out.println("SQL Exception: "+ e.toString());
       } 
       catch (ClassNotFoundException cE) 
       {
          System.out.println("Class Not Found Exception: "+ cE.toString());
       }
  
   return usernameExists;
   }
  </code></pre>
  
  <p>IF you can help in anyway I would be thankful!</p>