Java 14-17 Features

Java 17 is the latest Long-Term Support (LTS) release after Java 11.

Switch Expressions (Java 14)

Improved switch statement that can return a value and doesn't require break.

String day = "MONDAY";
int numLetters = switch (day) {
    case "MONDAY", "FRIDAY", "SUNDAY" -> 6;
    case "TUESDAY" -> 7;
    default -> day.length();
};

Text Blocks (Java 15)

Multi-line strings without ugly escape characters.

String json = """
    {
        "name": "Alice",
        "age": 30
    }
    """;

Records (Java 16)

Concise way to create immutable data classes.

public record User(String name, int age) {}

// Usage
User user = new User("Bob", 25);
System.out.println(user.name()); // Accessor (no get prefix)
System.out.println(user); // toString() auto-generated

Auto-generated methods:

• Constructor
• equals() and hashCode()
• toString()
• Accessors (name(), age())

Sealed Classes (Java 17)

Restrict which classes can extend or implement them.

public sealed interface Shape permits Circle, Square {}

final class Circle implements Shape {}
final class Square implements Shape {}

Pattern Matching for instanceof (Java 16)

No more explicit casting!

Object obj = "Hello";

// Old way
if (obj instanceof String) {
    String s = (String) obj;
    System.out.println(s.length());
}

// New way
if (obj instanceof String s) {
    System.out.println(s.length());
}

Quiz