Thread: My code return null, Why?

In the Main class I have the following

public class test {
 
    public static void main(String args[]){
 
 
 
        String separ;
        String lin = "/";
        String wind = "\\";
 
        String s = System.getProperty("file.separator");
        if (s != wind) 
          FileSeparatorExample.separator = lin;
 
        else 
            FileSeparatorExample.separator=wind;
 
      System.out.println(FileSeparatorExample.a);
}
 
}

in the another class

public class FileSeparatorExample {
 
 
    /**
     * @param args the command line arguments
     */
 
  public static String separator;
  public static String a ;
 
  public FileSeparatorExample(){
      this.a = FileSeparatorExample.separator;
  }  
 
  public static void lodA(){
      a = separator;
      return  ;
  }
 
 }

Why System.out.println(FileSeparatorExample.a);
return me "null"
how to fix?
I am a new in java, please help me!!!

Thanks