New features in Java 21: JDK 21

Published on May 23, 2023

Java developers, rejoice! JDK 21 has arrived with a slew of new features and improvements that promise to make your programming life easier and your applications more efficient. Here are some of the highlights of this release:

Records

One of the most anticipated features of JDK 21 is the introduction of records, a new kind of class that makes it easier to define simple data-orientated classes. Records provide a concise syntax for declaring classes that consist mainly of data fields, such as DTOs (Data Transfer Objects) and POJOs (Plain Old Java Objects). They also come with built-in methods, such as equals() and hashCode(), to make it easier to work with them.

Sealed Classes

JDK 21 also introduces sealed classes, which restrict the subclasses that can extend them. This feature provides more control over class hierarchies and helps prevent unexpected behaviour in code. Sealed classes also enable better error checking at compile-time, which can help catch bugs earlier in the development process.

Pattern Matching for instanceof

Another exciting feature of JDK 21 is the addition of pattern matching for instanceof expressions, which allows developers to extract information from objects in a concise and readable way. This feature makes it easier to write code that deals with complex data structures and reduces the need for boilerplate code.

Foreign Function and Memory Access APIs

JDK 21 also includes a set of new APIs for accessing foreign functions and memory, which can help developers write faster and more efficient code. These APIs enable Java code to interact with native C libraries and allow for more fine-grained memory management, which can be particularly useful in high-performance applications.

Performance Improvements

Finally, JDK 21 brings a number of performance improvements, including faster startup times and reduced memory usage. These improvements should help make Java applications run faster and more efficiently, which is always a welcome development.

Overall, JDK 21 is a significant release that brings a range of new features and improvements to the Java development community. Whether you’re a seasoned Java developer or just starting out, there’s something in this release to get excited about.