use java

1.

Based on your implementation of the partition(need to revise), and what is presented in the textbook, implement the following method:

public static void qsort(int[] vals)

which sorts the integer array vals using quicksort.

2.

Implement the following method in class Product:

public static double prod(double[] vals, int start)

the method computes the product of all numbers starting from start to the end in the array.