code: public void listContents() throws IOException {
          for (;;) {
              TarEntry entry = this.tarIn.getNextEntry();
  
              if (entry == null) {
                  if (this.debug) {
                      System.err.println("READ EOF RECORD");
                  }
                  break;
              }
  
              if (this.progressDisplay != null) {
                  this.progressDisplay.showTarProgressMessage(entry.getName());
              }
          }
      }
docs: Perform the "list" command and list the contents of the archive. NOTE That this method uses the progress display
  to actually list the conents. If the progress display is not set, nothing will be listed!