Example: FindSecondSmallestAndLargest_TwoPass in Java

// FindSecondSmallestAndLargest_TwoPass
public class Main {
    public static void main(String[] args) {
        int[] arr = {10, 5, 20, 15, 25, 5}; // Example array

        // Step 1: Handle edge cases
        if (arr.length < 2) {
            System.out.println("Array must contain at least two elements.");
            return;
        }

        // --- Find Second Smallest ---
        // Step 2: Initialize smallest and secondSmallest
        int smallest = Integer.MAX_VALUE;
        int secondSmallest = Integer.MAX_VALUE;

        // Step 3: First pass to find the absolute smallest
        for (int num : arr) {
            if (num < smallest) {
                smallest = num;
            }
        }

        // Step 4: Second pass to find the second smallest
        // Ensure it's not the same as the smallest
        for (int num : arr) {
            if (num < secondSmallest && num != smallest) {
                secondSmallest = num;
            }
        }

        // --- Find Second Largest ---
        // Step 5: Initialize largest and secondLargest
        int largest = Integer.MIN_VALUE;
        int secondLargest = Integer.MIN_VALUE;

        // Step 6: First pass to find the absolute largest
        for (int num : arr) {
            if (num > largest) {
                largest = num;
            }
        }

        // Step 7: Second pass to find the second largest
        // Ensure it's not the same as the largest
        for (int num : arr) {
            if (num > secondLargest && num != largest) {
                secondLargest = num;
            }
        }

        // Step 8: Print the results
        if (secondSmallest == Integer.MAX_VALUE) {
            System.out.println("No distinct second smallest element found.");
        } else {
            System.out.println("Second Smallest: " + secondSmallest);
        }

        if (secondLargest == Integer.MIN_VALUE) {
            System.out.println("No distinct second largest element found.");
        } else {
            System.out.println("Second Largest: " + secondLargest);
        }
    }
}