write java program contain four tasks that they must be excuted as hreads. your program should display the total timeto excute each thread.

the four tasks are:

Task one: enter and sort 100 double numbers in one dimensional array using merge sort algorithm.

Task two: enter 50 items to a linked list and display them back on the console.

Task three: multiply two (one-dimensional) arrays each with size of (20) and display the result on the console.

Task four: generate 500 integer numbers between (1 - 10000) and write them to a file and then sort them in increasing order using any sorting algorithm and display the sorted numbers on the console.