public static String trailingSlash(String value){
  if (value == null || value.endsWith("/")) {
    return value;
  }
  return value.concat("/");
}

public static String trailingSlash ( String value ) { if ( value == null || value . endsWith ( "/" ) ) { return value ; } return value . concat ( "/" ) ; }
appends a final slash on a given value .
