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2.6 Java Evolution & Modern LTS Features

← Back to Chapter 2: Java Overview & Memory Model

Java has moved from slow multi-year releases to a predictable 6-month release cadence with Long-Term Support (LTS) versions arriving every 2 years.

1. Landmark LTS Versions Overview​

Java 8 (2014) ─────► Java 11 (2018) ─────► Java 17 (2021) ─────► Java 21 (2023)
• Lambdas            • Modular JDK       • Records           • Virtual Threads (Loom)
• Streams API        • HTTP Client 2.0   • Sealed Classes    • Pattern Matching
• Optional & Time    • String methods    • Pattern Matching  • Sequenced Collections

2. Core Breakthroughs in Recent Java​

A. Records (Java 16)​

Eliminates boilerplate for immutable data carrier classes:

// Replaces 60 lines of boilerplate with one clean line!
public record UserProfile(long id, String username, String email) {}

B. Sealed Classes (Java 17)​

Restricts which subclasses or interfaces may extend or implement them:

public sealed interface PaymentResult permits Success, Failed, Pending {}

public record Success(String txId) implements PaymentResult {}
public record Failed(String reason) implements PaymentResult {}
public record Pending() implements PaymentResult {}

C. Sequenced Collections (Java 21)​

Introduces uniform interfaces (getFirst(), getLast(), reversed()) across List, Deque, and LinkedHashSet:

List<String> list = List.of("alpha", "beta", "gamma");
System.out.println(list.getFirst()); // "alpha"
System.out.println(list.getLast());  // "gamma"

D. Virtual Threads (Java 21 LTS - Project Loom)​

Lightweight user-mode threads managed directly by the JVM runtime instead of 1:1 mapping to OS kernel threads, allowing millions of concurrent socket connections with synchronous, blocking-style code.