Programming 2 with Java

Exercise: Prime Counter with Thread Pool

1. Implement a Callable class PrimeCounterTask whose constructor takes a minimum and a maximum number and whose call method returns the number of prime numbers in between using the utitlity class Primes.java.
2. Implement the program PrimeCounter which
   • takes a minimum and a maximum number as well as a number of threads as command line arguments
   • creates a thread pool with the specified number of threads
   • splits the given range into subranges and submits tasks each of which counts the prime numbers in one subrange
   • displays the total number of found prime numbers and the required runtime

   > java PrimeCounter 1 10000000 4
   664579 prime numbers found in 4.859 seconds
   

   (The table on the Wikipedia page of the prime-counting function can be used to verify the results.)
3. Run the program with different number of threads and compare the runtimes.

Solution