question: public static URL createURL ( String protocol , String host , String file ) throws MalformedURLException { return createURL ( protocol , host , - 1 , file ) ; }
target:  Creates a URL from the specified protocol name, host name, and file name. The default port for the specified protocol is used. <p/> This method is equivalent to calling the four-argument method with the arguments being protocol, host, -1, and file. No validation of the inputs is performed by this method.