using java:

all in 1 file please and thank you

Problem 1: Write a Python function that takes a positive integer n and returns the sum of the squares of all the positive integers smaller than n.

Problem 2: Given a list of n elements with each element between 1 and n. Write a Python program to determine whether there are any duplicates.

Problem 3: Write recursive Python function that computes the value of factorial function n! for any positive integer n.

Problem 4: Write a Python function that takes two square matrices of the same dimension as arguments and produces their product (another square matrix of the same dimension).

Problem 5: Write a recursive Python function for computing the nth Harmonic number, Hn = 1/i n i=1