Java 17 New Features

Java 17 is a version of the Java language, released in September 2021. It includes several new features and improvements. Below are some of the key new features in Java 17:

Sealed Classes (Further Improvements)

In Java 17, the sealed class feature has been further improved. This includes a new keyword permits and support for using sealed classes within switch statements.

Garbage Collector (GC) Improvements

The garbage collector in Java 17 has undergone several improvements, including optimizations for ZGC, Shenandoah, G1, and CMS. These enhancements aim to improve the performance and scalability of Java applications.

Switch Statement Support for Multiple Values

In Java 17, switch statements support matching multiple values simultaneously, which can reduce code duplication.

switch (status) {
    case ACTIVE:
    case PENDING:
        // Handle active or pending status
        break;
}

Classpath-Based JVM Startup Defaults to Deprecated

In Java 17, classpath-based JVM startup has been deprecated by default. This means that developers must use the modular approach to start Java applications.

Vector API

Java 17 introduces a new vector API that can improve the performance of vector operations.

import org.openjdk.jvm.vector.api.*;

Vector<Integer> result = Vector.of(1, 2, 3, 4).map(v -> v * 2);

Unicode 13.0

Java 17 includes support for Unicode 13.0, meaning Java now supports the latest Unicode standard.

Other Improvements

Java 17 also includes other improvements, such as enhancements to JVM startup performance, improvements to the JIT compiler, and a JVM compiler that supports the C++ 14 language specification.