Java 23 delivers significant performance and developer experience improvements with primitive types in patterns, enhanced ZGC garbage collector, and modern documentation capabilities. This release focuses on optimizing memory management, improving pattern matching performance, and enhancing code documentation quality for better maintainability.
September 2024
Java 23 delivers significant performance and developer experience improvements with primitive types in patterns, enhanced ZGC garbage collector, and modern documentation capabilities. This release focuses on optimizing memory management, improving pattern matching performance, and enhancing code documentation quality for better maintainability.
Java 23 introduces primitive types in pattern matching, enabling more efficient switch expressions and instanceof checks by avoiding unnecessary boxing operations. This feature significantly improves performance for numeric operations and provides cleaner syntax for type-specific processing, making pattern matching more practical for high-performance applications.
// Primitive patterns in switch
public String formatNumber(Object obj) {
return switch (obj) {
case int i when i > 0 -> "Positive integer: " + i;
case int i when i < 0 -> "Negative integer: " + i;
case int i -> "Zero";
case long l -> "Long value: " + l;
case double d -> "Double value: " + d;
case float f -> "Float value: " + f;
case null -> "null";
default -> "Unknown type";
};
}
// Pattern matching with primitive conversions
public void processNumber(Object value) {
switch (value) {
case byte b -> System.out.println("Byte: " + b);
case short s -> System.out.println("Short: " + s);
case int i -> System.out.println("Integer: " + i);
case long l -> System.out.println("Long: " + l);
case float f -> System.out.println("Float: " + f);
case double d -> System.out.println("Double: " + d);
case char c -> System.out.println("Character: " + c);
case boolean bool -> System.out.println("Boolean: " + bool);
default -> System.out.println("Not a primitive");
}
}
// Guarded primitive patterns
public String categorizeNumber(Object obj) {
return switch (obj) {
case int i when i >= 0 && i <= 100 -> "Percentage: " + i + "%";
case int i when i > 100 -> "Over 100: " + i;
case double d when d >= 0.0 && d <= 1.0 -> "Probability: " + d;
case double d -> "Other double: " + d;
default -> "Not a number";
};
}Java 23 enhances Javadoc with native Markdown support, enabling rich documentation with headers, lists, code blocks, and formatting. This feature improves API documentation readability, supports modern documentation practices, and makes it easier to create comprehensive developer guides directly within Java source code.
/**
* ## User Management Service
*
* This service provides comprehensive user management functionality including:
*
* - **User Registration**: Create new user accounts
* - **Authentication**: Verify user credentials
* - **Profile Management**: Update user information
*
* ### Usage Example
*
* ~~~java
* UserService service = new UserService();
* User user = service.createUser("john@example.com", "password123");
* ~~~
*
* ### Important Notes
*
* > **Warning**: Always validate user input before processing
*
* ### Related Classes
*
* - {@link User} - User entity class
* - {@link UserRepository} - Data access layer
* - {@link AuthenticationService} - Authentication utilities
*
* @author John Doe
* @version 2.0
* @since 1.0
*/
public class UserService {
/**
* Creates a new user account with the specified email and password.
*
* The method performs the following steps:
* 1. Validates the email format
* 2. Checks if the email is already registered
* 3. Hashes the password using BCrypt
* 4. Stores the user in the database
*
* @param email The user's email address (must be valid format)
* @param password The user's password (minimum 8 characters)
* @return The created {@link User} object
* @throws IllegalArgumentException if email or password is invalid
* @throws UserAlreadyExistsException if email is already registered
*
* @see #validateEmail(String)
* @see #hashPassword(String)
*/
public User createUser(String email, String password) {
// Implementation here
return null;
}
}Java 23 enables ZGC generational mode by default, providing improved memory management with reduced latency and better throughput. This enhancement separates young and old objects, allowing for more efficient garbage collection cycles and significantly better performance for applications with high memory allocation rates.
// ZGC Generational Mode Configuration
// Enable generational mode (default in Java 23)
// -XX:+UseZGC -XX:+ZGenerational
// Monitor ZGC performance
// -XX:+PrintGCDetails -XX:+PrintGCTimeStamps
// Example: High-performance application with ZGC
def runApp() {
List<byte[]> data = new ArrayList<>();
for (int i = 0; i < 1000000; i++) {
data.add(new byte[1024]);
if (i % 10000 == 0) {
System.out.println("Allocated " + i + " objects");
}
}
}
// ZGC provides low-latency garbage collection with pause times typically under 1ms.