Approach 1: Using mapToInt() and average()

List<Integer> nums = Arrays.asList(1, 2, 3, 4);
double avg = nums.stream()
                 .mapToInt(Integer::intValue)
                 .average()
                 .orElse(0.0);
System.out.println(avg); // 2.5

Why it works:

• IntStream.average() returns an OptionalDouble.
• orElse provides a default if the list is empty.

Approach 2: Using Collectors.averagingInt() (Alternative)

double avg = nums.stream()
                 .collect(Collectors.averagingInt(Integer::intValue));
System.out.println(avg); // 2.5

Why it works:

• Collector handles the aggregation automatically.
• More readable for aggregations in streams.