private String validateInputs(){
  String pomPath=pathEntry.getText();
  if (Strings.isNullOrEmpty(pomPath)) {
    return "GraphML file cannot be empty";
  }
  File pathFile=new File(pomPath);
  if (!pathFile.exists()) {
    return "GraphML file doesn't exist";
  }
  return null;
}

private String validateInputs ( ) { String pomPath = pathEntry . getText ( ) ; if ( Strings . isNullOrEmpty ( pomPath ) ) { return "GraphML file cannot be empty" ; } File pathFile = new File ( pomPath ) ; if ( ! pathFile . exists ( ) ) { return "GraphML file doesn't exist" ; } return null ; }
determine if the page has been filled in correctly .
