Need help with this Java problem:

Given an unsorted array of integers and an integer K, return K-th largest number in the array. Example: For a give array as : [10, 20, 15, 40, 80, 97, 26, 18, 92] If K is 1, K-th largest number is First largest number or the maximum, the function must return 97 If Kis 3, 3rd largest number or 80 must be returned. If Kis 7, 7th largest number which is 18 must be returned