What's Changed in Java Versions

Java's Journey Through Time

Java has been around for over two decades, powering robust applications across industries. It has consistently ranked as one of the most popular programming languages for building enterprise-grade applications. With the release of Java 23 and the end of support for Java 11, modern development now requires Java 17 as the baseline or newer versions.

Between Java 17 and 23, a lot has evolved. So, what’s changed? We’ll explore the journey Java has undergone to reach this level of maturity.

This article delves into the evolution of Java, the history of its versions, and the latest updates. If you're curious about the newest features in Java and how it’s shaping the future of development, keep reading.

Common Terms Used in Java Versions

1. JVM (Java Virtual Machine)
JVM is platform-dependent and executes the bytecode generated by the Java compiler. It provides the runtime environment for applications to execute. JVM manages the memory, registers, and garbage collection heap.

2. JRE (Java Runtime Environment)
JRE provides the environment to run Java programs. It includes the JVM and Java class libraries. Essentially, it’s a package of tools required to execute Java code.

3. JDK (Java Development Kit)
JDK is a complete toolkit for developing Java applications. It includes JRE, compilers, a debugger, and tools like Javadoc. It enables developers to create, compile, and run Java code. Since running Java programs is part of development, JDK requires a JRE.

4. Bytecode
Bytecode is the intermediate code generated by the Java compiler (saved in a .class file). With the help of JVM, this .class file can run on any system, making Java platform-independent.

Java 1.0
Java entered the scene with a promise that changed the software landscape forever—Write Once, Run Anywhere. It introduced the Java Virtual Machine (JVM), allowing developers to write code that could run on any device with a JVM, regardless of the underlying hardware. Memory management was automated, making developers’ lives easier. No major deprecations—this was just the start of it all.

Java 1.1
Java 1.1 began building on its foundations, adding inner classes and event listeners. These features made Java applications more dynamic and interactive, improving how developers could structure and manage their code.

Java 1.2
Java 1.2 was where things started to get exciting. It introduced the Collections Framework, Swing (for better GUIs), and the JIT compiler, which made performance much faster. This version made Java more capable of handling complex applications, especially with its introduction of the Java 2 Platform (J2EE) for enterprise applications.

Java 1.3
Java 1.3 focused on performance, thanks to the HotSpot JVM. The addition of Java 2 Platform, Enterprise Edition (J2EE) opened the door for building more scalable enterprise applications. While there weren’t any groundbreaking features, it set the stage for the rapid evolution to come.

Java 1.4
This version saw the introduction of regular expressions for easier text pattern matching, NIO (New I/O) for improved I/O performance, and Java Web Start, which allowed users to launch applications directly from a web browser. However, applets were slowly losing relevance and began to be deprecated in favor of more modern web technologies.

Java 5
Java 5 (also known as 1.5) was one of the most significant updates in Java’s history. It introduced generics, annotations, and enumerated types, making Java code safer and more efficient. It also introduced the enhanced for-loop, which simplified iteration over collections. It was a major shift—so big, it was almost named Java 1.5 instead.

Java 6
Java 6 focused heavily on performance improvements, including enhancements to the Java Compiler API and Java Virtual Machine. It also brought in features for easier web services integration. Java became more powerful, but no major deprecations took place—Java 6 was about refining what already existed.

Java 7
With Java 7, the language got a lot more developer-friendly. Features like try-with-resources and the diamond operator made coding cleaner. The Fork/Join framework was introduced for better parallel processing. However, applets were officially deprecated, signaling a shift away from Java’s use in browsers.

Java 8
Java 8 is considered one of the most significant updates ever, with lambda expressions and streams bringing functional programming concepts to the language. This made Java much more concise and expressive. The new Date/Time API replaced the outdated Date class, and default methods in interfaces allowed for more flexible code. Still, Applets were officially removed, as they were no longer relevant.

Java 9
With Java 9, modularity was the big focus. The introduction of Project Jigsaw allowed developers to break down applications into smaller, more manageable modules, improving scalability. JShell, the interactive REPL, allowed for faster testing and experimentation. This release also saw the deprecation of some legacy Java EE modules as the shift to modern web frameworks took hold.

Java 10
Java 10 brought local variable type inference (var), making it easier to declare variables without explicitly specifying the type. The G1 garbage collector received improvements for better performance. There were no big deprecations, just a continued push toward a more efficient and flexible Java.

Java 11
Java 11 was the first LTS (Long-Term Support) release since Java 8, making it a critical version for enterprises looking for stability. It introduced the HTTP Client API for better web communication and marked the removal of Java EE and CORBA modules, which had become outdated. As an LTS release, it became a popular choice for many developers needing stable, long-term support.

Java 12
Java 12 introduced features like the JVM Constants API and the experimental Shenandoah garbage collector, designed to reduce pause times. It also deprecated the RMI Activation mechanism, as modern applications no longer needed it. These changes made Java even more performant and scalable.

Java 13
Java 13 made working with strings easier by introducing text blocks for multi-line strings. This version also focused on better garbage collection and performance optimizations. There were no major deprecations in this release, just continued improvements.

Java 14
Java 14 brought records (a feature for immutable data classes), pattern matching for instanceof, and enhancements in memory management. ZGC (Z Garbage Collector) was also introduced in experimental form. The major deprecation here was the Nashorn JavaScript engine, as more modern JavaScript engines were being adopted.

Java 15
Java 15 introduced sealed classes, which restrict the types that can extend or implement them, bringing greater control over your code. The foreign-memory access API continued evolving, offering new ways to interact with memory outside of the JVM. The RMI Activation API was officially deprecated.

Java 16
With Java 16, pattern matching for instanceof became more mature, and the Records feature was fully introduced. The Foreign Function & Memory API continued to evolve, making Java better suited for native integration. Java 16 was more about solidifying features rather than introducing any major deprecations.

Java 17
Java 17, an LTS release, brought sealed interfaces and improved garbage collection methods like ZGC and Shenandoah. It also strongly encapsulated JDK internals for better security. There was also a deprecation of some old security providers, marking a shift toward more modern and secure APIs.

Java 18
Java 18 focused on improving memory handling and the Foreign Function & Memory API to better interact with native code. It also made UTF-8 the default charset, aligning Java with modern internationalization standards. This version was more about internal improvements rather than outwardly visible changes.

Java 19
Java 19 began exploring Project Loom (lightweight concurrency) and continued to refine pattern matching. The foreign-memory access API was further polished, and value types began making their way into the language. These are steps towards modernizing Java for complex, high-performance applications.

Java 20
Java 20 further refined Project Loom and pattern matching, with enhanced support for value types and new concurrency models. Foreign memory access continued to evolve, making Java more efficient in handling native code and improving performance for resource-heavy applications.

Java 21 LTS
Java 21, another LTS release, continued improvements in Project Loom, record patterns, and scalability. It also introduced better memory management and finalized some of the earlier features. The deprecation of certain legacy concurrency models marked a final step in pushing Java toward more modern paradigms.

Java 22
Java 22 is about future-proofing the language with finalized support for Project Loom and continued improvements in concurrency. Pattern matching becomes even more refined, and new tools for scalable applications emerge. Java is now more capable than ever for handling high-performance, complex systems.

Java 23
The latest release, Java 23, expands pattern matching and enhances native memory management with the Foreign Function & Memory API. This makes Java even more powerful for modern applications that interact with low-level system resources. Java 23 is all about scalability, performance, and developer productivity, ensuring that Java remains relevant for years to come.

Which Version Should You Use?

For beginners, starting with a recent LTS version like Java 17 or 21 is generally a good idea. These versions are well-supported and have all the latest features. So, there you have it. A beginner-friendly look at the evolution of Java. Don't be overwhelmed by the numbers. Just remember that each version builds upon the previous one, making Java a more powerful and versatile language. Happy coding.

The above is the detailed content of What's Changed in Java Versions. For more information, please follow other related articles on the PHP Chinese website!