Oracle JDK17给Java开发新视野（oracle jdk17）

Oracle JDK 17: Giving Java Development a New Look

Java has been a popular programming language for the development of robust and scalable applications. Since its inception, Java has gone through numerous transformations and upgrades to stay on top of the latest technological trends. Oracle, the primary contributor to the Java platform, announced the release of JDK 17, the latest version of Java Development Kit, in September 2021. Oracle JDK 17 brings several new features and improvements that elevate the Java programming landscape.

One of the most visible changes in the new release is the addition of new language features, including sealed classes and interfaces, pattern matching, and switch expressions. Sealed classes and interfaces provide developers with more control over the class hierarchy, allowing them to define a fixed set of subtypes. Pattern matching simplifies the process of writing complex conditional statements by providing more expressive syntax to match agnst patterns. Switch expressions now support yield, a convenient way to return a value from a switch statement.

Another significant update in Oracle JDK 17 is the addition of preview features. Preview features are new additions that are not fully implemented or tested and should only be used in development environments. Some of the preview features added in JDK 17 include the enhanced Foreign Function and Memory API, the enhanced OpenSSL connector, and the Vector API. The Vector API provides a scalable and efficient way to perform math operations on arrays and matrices, potentially improving the performance of machine learning algorithms.

Oracle JDK 17 also includes several performance improvements that make Java applications faster and more efficient. The new G1 collector algorithm, for instance, improves the efficiency of the garbage collector, reducing pauses and improving throughput. Another performance improvement comes from the introduction of records, a new way to define data classes. Records provide a more efficient way to create immutable data classes, reducing the amount of boilerplate code required.

Furthermore, Oracle JDK 17 brings several security updates to improve the safety and reliability of Java applications. The new release has removed the insecure SHA-1 hash algorithm and introduced updates to key algorithms for secure communications with servers. The new TrustAnchor class simplifies the management of trusted root certificates, making it easier to use secure connections.

In conclusion, Oracle JDK 17 is a significant milestone for Java Development. It provides developers with new tools and features to create more efficient and reliable applications. The new language features, performance improvements, and security updates enable Java developers to stay ahead of their competition in the ever-evolving tech industry. As the Java community continues to grow and evolve, Oracle JDK 17 is an excellent addition to Java’s rich history of development tools and frameworks.

Below is a code example demonstrating the use of the new sealed classes feature in Oracle JDK 17:

public abstract sealed class Shape permits Square, Circle {
    public abstract double area();
}
final class Square extends Shape {
    private final double side;
    public Square(double side) {
        this.side = side;
    }

    @Override
    public double area() {
        return side * side;
    }
}

final class Circle extends Shape {
    private final double radius;
    public Circle(double radius) {
        this.radius = radius;
    }

    @Override
    public double area() {
        return Math.PI * radius * radius;
    }
}

In the code above, we define an abstract sealed class called Shape with two subtypes, Square and Circle. Sealed classes and interfaces provide developers with more control over the class hierarchy, allowing them to define a fixed set of subtypes. Here, we define the Square and Circle subtypes to have different implementations of the area method.