Problem
Write a program that prompts the user for the name of a Java source code file. The program shall read the source code file and output the contents to a new file named the same as the input file, but with a .txt file name extension (e.g., if the input file is foo.java then the output file shall be named foo.java.txt). Each line of the input file shall be numbered with a line number (formatted as shown below) in the output file.