Write a program in java

that takes the numbers in $2$ sorted files and merges them into a third.

The program must merge the files. not input the $2$ files into $1$ big array, and sort them $--$so that the numbers in the output file are sorted

Input the file names, and be sure to check the file exists. no need to check if the output file exists, only the $2$ input files

after the merge is complete

read the numbers from the output file and print them to the screen

note$--$either of the $2$ input files may have more numbers than the other

based on the book "Building Java Programs: A Back to Basics Approach, $5/$ed$".$ Im limited to build the program with the material from chapter $1-6.$

avoid BufferedReader and FileReader $,$try$/$catch$,$ IOException don't use them at all. make it as simple as u can