Java 8 Crash Course in One Shot 🔥 | From Basics to Advanced

Java 8 was a game-changer for the language — and if you're preparing for Java interview questions, working in a product-based company, or simply want to deepen your understanding of Java 8 features, this is the only video you need. In this full course, we cover every major Java 8 new feature from scratch, with clear explanations and real-world context — so you don't just memorize answers, you actually understand the logic behind them. 🔥 What You'll Learn in This Video: ✅ Default Methods in Interface — Why Java 8 introduced default methods, how they solve the backward compatibility problem, and how Java handles the diamond problem and conflict resolution when multiple interfaces provide the same default method. We also cover the difference between Object class methods and default methods, and what happens with method overriding. ✅ Static Methods in Interface — Understand why static methods were added to interfaces in Java 8, the rules around static method in interface vs class, whether static methods can be overridden, and real-world use cases like utility and helper methods in interfaces. We also clarify method hiding vs overriding in Java. ✅ Functional Interface & Lambda Expressions — A complete breakdown of what a functional interface in Java 8 is, the role of the @FunctionalInterface annotation, and how lambda expressions replace verbose anonymous inner classes. We compare lambdas to abstract classes and explain functional programming in Java with practical examples. ✅ Predicate, Function, Consumer & Supplier — Deep dive into the four core built-in functional interfaces in Java 8: Predicate — test() method, real-world filtering use cases Function — apply() method, transforming data Consumer — accept() method, consuming data without returning Supplier — get() method, supplying values lazily ✅ Method Reference — When and why to use method references over lambda expressions, with examples covering static method reference, instance method reference, and constructor reference in Java 8. We also answer the classic interview question: what's the difference between lambda vs method reference? ✅ Optional Class — How to avoid NullPointerException in Java using the Optional class in Java 8. We cover all key methods — isPresent(),ifPresent(),orElse(),orElseGet(),orElseThrow(),of(), and ofNullable()— and explain the difference between orElse vs orElseGet, which is a frequently asked Java 8 interview question. ✅ Stream API in Java 8 — This section goes far beyond basic syntax. We start with the fundamentals — what a Stream actually is and the key difference between the Stream interface vs the Stream method, a distinction most tutorials skip but interviewers love to ask about. From there, we break down how the Stream API is built on top of the four core functional interfaces — Predicate, Consumer, Supplier, and Function — so you understand what's happening under the hood when you call filter(), map(), or forEach(), not just how to use them. Then, we go deep on collect() and Collectors in Java — Collectors.toList(), Collectors.toMap(), and Collectors.toSet() — followed by stream methods like findFirst(), findAny(), anyMatch(), allMatch(), noneMatch(), and sorted(). We also cover primitive streams — IntStream, LongStream, and DoubleStream — including when and why to use them over the generic Stream. Finally, we cover parallel streams in Java 8: how they work, when they actually help performance, and the trade-offs you need to know before using them in a real codebase — a topic that consistently comes up in senior-level Java stream interview questions. ✅ Date-Time API — Why the old Date and Calendar classes were broken, and how Java 8 Date and Time API fixes them with immutability and thread-safety. We cover LocalDate, LocalTime, LocalDateTime, ZonedDateTime, ZoneId, Duration.between(), Period.between(), LocalDate.now(), and LocalDate.of()— with a clear comparison of Java 8 Date-Time API vs the old Date and Calendar. 🎯 This video is for you if: 1. You're preparing for Java 8 coding interview questions at product or service-based companies 2. You want a single, structured Java 8 tutorial instead of jumping between random resources 3. You want to master Java streams, lambda expressions, and the Optional class with clarity 00:00:00 : Default Methods in Interface 00:17:35 : Static Methods in Interface 00:25:35 : Functional Interface & Lambda Expressions 00:49:32 : Predicate, Consumer, Function, Supplier 01:05:54 : Method Reference 01:31:15 : Optional Class 01:54:36 : Stream API 02:38:35 : Date & Time API #java8 #java8features #java8tutorial #javainterviewquestions #streamapi #lambdaexpressions #functionalinterface #optionalclass #javatutorial #springboot #javaprogramming #java8interviewquestions #methodreference #predicate #dateandtimeapi #javatutorialforbeginners #functionalProgramming #parallelstreams #java8coding #interview #springboot #java Instagram :   / the.curious_coder