code: public String getCmdLineArg() {
          StringBuilder builder = new StringBuilder("  --server-groups=");
          boolean foundSelected = false;
          for (JCheckBox serverGroup : serverGroups) {
              if (serverGroup.isSelected()) {
                  foundSelected = true;
                  builder.append(serverGroup.getText());
                  builder.append(",");
              }
          }
          builder.deleteCharAt(builder.length() - 1); // remove trailing comma
  
          if (!foundSelected) return "";
          return builder.toString();
      }
docs: Return the command line argument
  
  @return  "  --server-groups=" plus a comma-separated list
  of selected server groups.  Return empty String if none selected.