gintvile.java

public class GintvileFile {
  private String name;
  private String contents;
  public GintvileFile() {
    this.contents = "";
  }
  public String getContents() {
    return contents;
  }
}

public class FileTxt extends GintvileFile {
  public FileTxt() {
    this.contents = "contents"; // <-- contents that you read from that file
  }
}

public class GintvileFolder {
  private int filesContained;
  private int foldersContained;
  public GintvileFolder() {
    this.filesContained = 0; // <-- how many files in this folder, so that you can iterate later
    this.foldersContained = 0; // <-- how many folders...
  }
}