Java 17 features
javaSealed Classes and Interfaces
Sealed CLasses and Interfaces restrict with other classes and interfaces can extend or implement them. The provides a way to enforce certain design constraints and maintain better control over class hierarchy.
Sealed classes example
public sealed class Transaction permits Deposit, Withdrawal, Transfer {
// common properties and methods for transactions
}
public final class Deposit extends Transaction {
// Properties and methods for deposit
}
public final class Withdrawal extends Transaction {
// Properties and methods for withdraw
}
public final class Transfer extends Transaction {
// Properties and methods for transfer
}
Sealed interfaces example
public sealed interface Vehicle permits Car, Truck, Motorcycle {
// common properties and methods for Vehicles
}
public final class Car implements Vehicle {
// Properties and methods for car
}
public final class Truck implements Vehicle {
// Properties and methods for truck
}
public final class Motorcycle implements Vehicle {
// Properties and methods for motorcycle
}
Pattern Matching for intanceof
Pattern matching for intanceof allows for more concise and readable code when checking an object’s type and extracting its files.
Example:
Object obj = "Hello, World!";
if (obj instanceof String str) {
System.out.println(str.toUpperCase());
}
public void processShape(Shape shape) {
if (shape instanceof Circle circle) {
System.out.println("Circle radius: " + circle.radius());
} else if (shape instanceof Rectangle rectangle) {
System.out.println("Rectangle width: " + rectangle.getWidth());
System.out.println("Rectangle height: " + rectangle.getHeight());
} else {
System.out.println("Unknown shape");
}
}
Benefits:
- Cleaner Code: Reduces the redundancy by combining the type checking and casting.
- Improved Readability: Makes it easier to follow the logic of the code.
- Type Safety: Helps avoid potential ClassCastException at runtime.
Records
Records in Java provide a compact and clear syntax for creating classes that are primarily used to store data. Records simplify the creation of data-carrying classes by automatically generating essential methods like equals(), hashCode(), and toString().
Example:
public record Point(int x, int y) {}
public class Main {
public static void main(String[] args) {
Point point = new Point(5, 10);
System.out.println(point.x()); // Output: 5
System.out.println(point.y()); // Output: 10
System.out.println(point); // Output: Point[x=5, y=10]
}
}
Benefits of Records:
- Conciseness: Reduces boilerplate codes.
- Readability: Makes intentions clear; it’s obvious that the class is just for storing data.
- Immutability: Records are implicitly final and all fields are private and final.
Stronger Encapsulation
Stronger Encapsulation refers to the initiative to restrict access to internal APIs, even via reflection, to improve the stability and security of the platform. It’s a way of ensuring that internal classes and members, which are meant to be hidden, remain inaccessible from outside the module.
Benefits of Stronger Encapsulation
- Improved Security: By preventing unauthorized access to internal classes and methods.
- Stability: By hiding internal APIs, it reduces the risk of breaking changes affecting external code.
- Better Modular Design: Encourages more thoughtful and deliberate design of module boundaries and dependencies.
Enhanced Pseudo-Random Number Generators
New interfaces and implementations for Pseudo-Random Number Generators (PRNG) to support different algorithms interchangeably.
New macOS Rendering Pipeline
This update implements a new rendering pipeline for the macOS using the Apple Metal API.
Deprecation of the Applet API
The Applet API has been deprecated for removal, as many web browsers have already removed support for Java plugins.
Vector API
This feature provides native support for vector operations, which can improve program performance using hardware acceleration. It is particularly useful for applications that involve heavy numerical computations, such as image processing, signal processing, encryption and bioinformatics.