https://devops-monk.com/tags/lambda/Recent content in Lambda on Devops MonkHugoen-usMon, 04 May 2026 00:00:00 +0000https://devops-monk.com/tutorials/java8/java8-best-practices/Mon, 04 May 2026 00:00:00 +0000https://devops-monk.com/tutorials/java8/java8-best-practices/Streams Best Practices Do: Use streams for transformations and aggregations // Good: filter → transform → collect List<String> premiumNames = customers.stream() .filter(Customer::isPremium) .map(Customer::getName) .sorted() .collect(Collectors.toList()); // Good: aggregation Map<String, Long> countByCity = customers.stream() .collect(Collectors.groupingBy(Customer::getCity, Collectors.counting())); Don’t: Use streams for simple indexed iteration // Bad: stream for something a loop does more clearly IntStream.range(0, list.size()) .forEach(i -> System.out.println(i + ": " + list.get(i))); // Good: traditional loop wins here for (int i = 0; i < list.https://devops-monk.com/tutorials/java8/lambdas/Mon, 04 May 2026 00:00:00 +0000https://devops-monk.com/tutorials/java8/lambdas/The Problem Lambdas Solve Before Java 8, passing behaviour as a value required an anonymous inner class: // Java 7: sort a list of strings by length Collections.sort(names, new Comparator<String>() { @Override public int compare(String a, String b) { return Integer.compare(a.length(), b.length()); } }); // Run in a new thread new Thread(new Runnable() { @Override public void run() { System.out.println("Hello from thread"); } }).start(); This works, but the boilerplate-to-intent ratio is terrible.https://devops-monk.com/tutorials/java8/method-references/Mon, 04 May 2026 00:00:00 +0000https://devops-monk.com/tutorials/java8/method-references/What Are Method References? A method reference is a compact syntax for a lambda expression that does nothing except call an existing method. If a lambda’s entire body is a method call, a method reference is almost always clearer. // Lambda names.forEach(s -> System.out.println(s)); // Method reference — identical behaviour, fewer characters, clearer intent names.forEach(System.out::println); The :: operator is the method reference operator. It does not call the method — it creates a reference to it, which the compiler wraps into a lambda that calls the method.