Java Stream Practice questions : Given a list of numbers, find the duplicate numbers Given a list of transactions with date, amount, and category, find the category with the highest total transaction amount in each month of 2024. Return a map of month to category. From a list of employees with name, department, salary, and years of experience, find departments where the average experience is above 5 years AND the average salary is below the company-wide average salary. Given a list of product orders with customer ID, product name, quantity, and price, find customers who have bought all products at least once (complete product coverage). Return their customer IDs.