Java program for file processing.

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Note: The code should be a working solution. Do not provide half a solution. Please make sure the entire code is visible in the post and not just a part of the code. The code is executing without any compiler errors. Include the screenshot of the execution. Otherwise, I will downvote because this is the third time I am asking the same question and getting only half solution which is not acceptable.

Given a list of [FileName, FileSize, [Collection]] - Collection is optional, i.e., a collection can have 1 or more files. Same file can be a part of more than 1 collection.

How would you design a system?

To calculate total size of files processed.

To calculate Top K collections based on size.

Example:

file1.txt(size: 100)

file2.txt(size: 200) in collection "collection1"

file3.txt(size: 200) in collection "collection1"

file4.txt(size: 300) in collection "collection2"

file5.txt(size: 100)

Output:

Total size of files processed: 900

Top 2 collections:

collection1 : 400

collection2 : 300

Follow up questions:

1] Modularise the code and write Junit tests

2] Use design pattern suitable.

3] Concurrent calls handling - Synchronization

4] Tradeoff between speed and storage of file information

5] If you used list not Set , then why set etc.