Assume an Employee class with an id field: Approach 1: Using toMap() (Keeps first occurrence) Approach 2: Using TreeSet with Comparator (Keeps first per comparator) Summary:

Approach 1 — Using Stream.concat Approach 2 — Using Stream.of + flatMap Explanation:

Approach 1 — thenComparing Approach 2 — Combined Lambda Comparator Explanation:

Approach 1 — Using Comparator.comparing Approach 2 — Using a Lambda Comparator Explanation:

Approach 1 — Using min with a Comparator Approach 2 — Sorting and Taking First Explanation:

Approach 1 — Using max with a Comparator Approach 2 — Using reduce Pairwise Explanation:

Approach 1 — Using groupingBy and counting Approach 2 — Using toMap with a Merge Function Explanation:

In many applications, you may need to identify the second-largest (or second-highest) number in a collection. Java Streams provide elegant and concise ways to achieve this with functional-style operations. Consider the example list: Notice that the list may contain duplicates, so we need to handle that to ensure correctness. Approach 1: Using distinct(), sorted(), and…

Approach 1: Using Collectors.partitioningBy() Why it works: Approach 2: Using Collectors.toCollection (Alternative) Why it works:

Approach 1: Using Stream.generate() Why it works: Approach 2: Using Random.ints() (Alternative) Why it works: