object definition in java within a special condition

Question

I want to use the lang variable in my code, and give the value in the if command. Is the below code possible in .jsp page ?

<%
  String language = "EN";
  EN lang;
  if (language.equals("EN")){
    lang = new EN();
  }
  else if (language.equals("FR")){
    lang = new FR();
  }
%>
// html ...
<% out.print(lang.variable1); %>

i got this error :

incompatible types; found: mypackage.FR, required: mypackage.EN

code please ?

Answer 1

Are classes EN and FR derived from a common interface or abstract class? If yes, you can change EN lang; to <abstractClass> lang;. If not, you can start thinking of refactoring your class. An ugly solution would be to use Object lang;

Answer 2

 lang = new FR();     

It should be

 lang = new ER();     //in else if

here you are assigning an Object of FR to the reference of ER.

I would like to know what is the relationship between FR and ER ?

Answer 3

lang = new FR();

You are assigning an object of type FR to lang which is of type EN and is clearly wrong.

Answer 4

Your code should look something like this:

interface Lang {

}

class EN implements Lang {

}

class FR implements Lang {

}

<%
  String language = "EN";
  Lang lang;
  if (language.equals("EN")){
    lang = new EN();
  }
  else if (language.equals("FR")){
    lang = new FR();
  }
%>

Answer 5

Instead of declaring lang as EN, declare it as an instance of the superclass of EN and FR (perhaps Lang ?)