What changed in modern Java (8 to 21) that every developer should know?

Answer

• Java 8: lambdas, streams, Optional, default methods, java.time API.
• Java 9 to 11: modules, var for local variables, List.of, HTTP client; Java 11 is an LTS (long-term support).
• Java 14 to 17: records, switch expressions, text blocks, sealed classes, pattern matching for instanceof; Java 17 is an LTS.
• Java 21 (LTS): virtual threads, record patterns, pattern matching for switch, sequenced collections.
• Say: "I mainly target the current LTS and use records, streams and Optional daily."

// Java 17+ examples
record User(String name, int age) {}

String text = """
    multi-line
    text block""";

Object o = 42;
if (o instanceof Integer i && i > 40) { System.out.println(i); }

String label = switch (day) {
    case SATURDAY, SUNDAY -> "weekend";
    default -> "weekday";
};

Key terms

• Stream API
• Record
• Lambda expression
• Optional
• Generics
• Virtual thread
• HTTP
• API