Код ! изменяет ли переменные динамически

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Код,который должен изменить переменные a,b, c, d, если a вводится в подсказке значение a инициализируется на" ", но b, c и d не инициализируются

public class BufferedReaderFromUserAnd
{
  private static final String FILENAME = "F:/Android.txt";

  public static void main(String args[]) throws IOException
  {
    BufferedWriter bw = null;
    FileWriter fw = null;

    try
    {
      fw = new FileWriter(FILENAME);
      bw = new BufferedWriter(fw);

      BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
      System.out.print("Word1: ");
      String Word1 = reader.readLine();
      System.out.print("Word2: ");
      String Word2 = reader.readLine();
      System.out.print("Word3: ");
      String Word3 = reader.readLine();
      System.out.print("Word4: ");
      String Word4 = reader.readLine();
      System.out.print("Y: ");
      String y = reader.readLine();
      String a = reader.readLine();
      String b = reader.readLine();
      String c = reader.readLine();
      String d = reader.readLine();      
           
      if(y.compareTo(a)==0)
      {                
        b = "not" ;       
        c = "not" ;                       
        d = "not" ;       
      }                
          
      if(y.compareTo(b)==0)
      {                
        a = "not" ;       
        c = "not" ;                       
        d = "not" ;       
      }
          
      if(y.compareTo(c)==0)
      {                
        b = "not" ;       
        a = "not" ;                       
        d = "not" ;       
      }                
          
      if(y.compareTo(d)==0)
      {                
        a = "not" ;       
        c = "not" ;                       
        d = "not" ;       
      }    
      

      String n = reader.readLine();

      bw.write("<input type='radio' name='rbnNumber' value='You selected (a) " + Word1 + "  which is " + a +  " the correct answer' />(a) "  + Word1 + "<br/>");
      bw.write("<input type='radio' name='rbnNumber' value='You selected (a) " + Word2 + "  which is " + b +  " the correct answer' />(a) "  + Word2 + "<br/>");
      bw.write("<input type='radio' name='rbnNumber' value='You selected (a) " + Word3 + "  which is " + c +  " the correct answer' />(a) "  + Word3 + "<br/>");
      bw.write("<input type='radio' name='rbnNumber' value='You selected (a) " + Word4 + "  which is " + d +  " the correct answer' />(a) "  + Word4 + "<br/>");
    }
    catch (IOException e) {
      e.printStackTrace();
    }
    finally
    {
      try {
        if (bw != null)
          bw.close();
        if (fw != null)
          fw.close();
      }
      catch (IOException ex) {
        ex.printStackTrace();
      }
    }
  }
}

если a вводится в командной строке то результат будет следующим

<input type='radio' name='rbnNumber' value='You selected (a) Android  which is  the correct answer' />(a) Android<br/>
<input type='radio' name='rbnNumber' value='You selected (a) CS  which is  the correct answer' />(a) CS<br/>
<input type='radio' name='rbnNumber' value='You selected (a) OS  which is  the correct answer' />(a) OS<br/>
<input type='radio' name='rbnNumber' value='You selected (a) Code  which is  the correct answer' />(a) Code<br/>

требуется :

<input type='radio' name='rbnNumber' value='You selected (a) Android  which is  the correct answer' />(a) Android<br/>
<input type='radio' name='rbnNumber' value='You selected (a) CS  which is not  the correct answer' />(a) CS<br/>
<input type='radio' name='rbnNumber' value='You selected (a) OS  which is not  the correct answer' />(a) OS<br/>
<input type='radio' name='rbnNumber' value='You selected (a) Code  which is not the correct answer' />(a) Code<br/>

Что я уже пробовал:

Искомый код и классы Java

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