Write a program which takes list of log files as input and outputs number of exceptions grouped by time range and exception type. At any moment x files should be processed simultaneously if more than x files are remaining. For input assume 20 log files and x(no of files to be processed simultaneously) to be 5.

The format of the log file is as following:-

requestId timeStamp text

586763334343 1523718907817 NullPointerException

586763434443 1523718907818 IllegalAgrumentsException

The fields are separated by space. You can assume that the text field in the file contains only exception name and the file only contains exceptions. The output should be grouped by time range(15 mins) and exception type.

For parallel processing use ExecutorService.

Output Format:-

15:00-15:15 NullPointerException 30

15:00-15:15 IllegalAgrumentsException 25