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shantanu mahakale
shantanu mahakale

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Quick Recap: Java Versions

#java #programming #tutorial

Here’s a practical summary of the most useful Java features added from Java 8 to recent versions, focusing on what developers actually use in daily coding.

Java 8 (Most Impactful Release)

  • Lambda Expressions → Functional programming
  • Stream API → Declarative data processing
  • Functional Interfaces (@FunctionalInterface)
  • Default & Static Methods in Interfaces
  • Optional Class – Avoid null checks
  • Date/Time API (java.time) – Replaces old Date/Calendar
  • Method References (:: operator)

👉 Most popular version in production even today.

Java 9

  • Modules (JPMS) – module-info.java
  • JShell – REPL for testing code quickly
  • Factory Methods for Collections 
List.of(1, 2, 3);
Set.of("A", "B");
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  • Improved Stream API: takeWhile(), dropWhile(), iterate()

Java 10

  • Local Variable Type Inference (var) 
var name = "Shantanu";
var list = new ArrayList<String>();
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👉 Not like JavaScript – only for local vars.

Java 11 (LTS Release)

  • HTTP Client API (modern replacement for HttpURLConnection) 
HttpClient client = HttpClient.newHttpClient();
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  • String Methods 
"hello".isBlank();
"line1\nline2".lines();
"test".repeat(3);
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  • var allowed in lambda params

👉 Very stable & widely used enterprise version after Java 8.

Java 14

  • Switch Expressions (Enhanced) 
int result = switch(x) {
case 1 -> 100;
case 2 -> 200;
default -> 0;
};
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  • Records (Preview) – Lightweight data classes
  • NullPointerException with details

Java 15

  • Text Blocks (Multiline Strings) 
String json = """
{
"name": "John"
}
""";
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👉 Clean JSON, SQL, HTML formatting.

Java 16

  • Records (Final Release) 
public record User(String name, int age) {}
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  • Pattern Matching for instanceof 
if (obj instanceof String s) {
System.out.println(s.toUpperCase());
}
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Java 17 (LTS)

  • Sealed Classes 
public sealed class Animal permits Dog, Cat {}
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  • Switch pattern matching (Preview)
  • Stronger encapsulation & security updates

👉 Current long-term support (LTS) version used widely in new projects.

Java 19 / 20 (Preview Features)

  • Virtual Threads (Project Loom) 
Thread.startVirtualThread(() -> {
// lightweight threads
});
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👉 Massive performance boost for high-concurrency apps.

  • Structured Concurrency Better control over multi-threading workflows.

Java 21 (LTS – Most Recent Major)

  • Virtual Threads (Final) – Game changer for performance
  • String Templates (Preview) 
STR."Hello, ${name}!"
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  • Sequenced Collections – Ordered access to elements
  • Record Patterns – Destructuring syntax
  • Pattern Matching Enhancements

👉 Consider upgrading if starting a new application.

Summary Table

Version Key Features
Java 8 Lambdas, Streams, Optional, Date API
Java 9 Modules, JShell
Java 10 var keyword
Java 11 HTTP Client API, String methods
Java 14 Switch expressions, Records (preview)
Java 15 Text Blocks
Java 16 Records, Pattern Matching
Java 17 LTS, Sealed Classes
Java 19/20 Virtual Threads (preview)
Java 21 Virtual Threads (final), String templates

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