Java 22 Polishes the Future of Java

Java 22, released in March 2024, is another feature release (non-LTS), and it continues to refine many of the capabilities introduced in Java 21.

With Java 21 having locked in virtual threads, pattern matching, and record patterns, Java 22 shifts focus to enhancing preview features, streamlining syntax, and finalizing some key APIs.

This release is especially useful for developers building scalable systems, experimenting with native code, or working on cleaner syntax in modern Java.

Let’s take a look at what Java 22 brings to the table.

✅ Final Features in Java 22

1. Foreign Function & Memory API — JEP 454

The Foreign Function & Memory (FFM) API is now finalized, replacing JNI for many use cases. It provides a powerful and safe way to:

• Call native functions (e.g., from C)

• Allocate and manage off-heap memory

• Share memory with native processes

For example:

try (Arena arena = Arena.ofConfined()) {

MemorySegment segment = arena.allocate(100);

// Work with native memory

}

This final version includes:

• Stable memory layout APIs

• Linker for native function calls

• SymbolLookup for native symbol resolution

2. Statements Before super() — JEP 447

This long-requested enhancement allows statements before super() in constructors—as long as they don’t reference this.

Example:

class Child extends Parent {

Child(String raw) {

String cleaned = raw.trim();

super(cleaned); // Now allowed

}

}

Why it matters:

• Useful for validating or preparing constructor arguments

• Improves readability and modularity

🧪 Preview and Incubator Features

3. Unnamed Variables and Patterns (Preview) — JEP 443

You can now use _ as a placeholder for:

• Unused variables

• Unused pattern bindings

For example:

if (obj instanceof String _) {

System.out.println("It’s a String, but we don’t care what it is.");

}

This reduces boilerplate and improves clarity in pattern matching.

4. Unnamed Classes and Instance main Methods (2nd Preview) — JEP 456

First previewed in Java 21, this feature simplifies the process of writing small programs.

For example:

void main() {

System.out.println("No class declaration required!");

}

This version enhances integration with tooling and improves handling of default behaviors.

5. String Templates (2nd Preview) — JEP 459

String Templates continue to evolve with better IDE support, performance, and custom processors.

For example:

String name = "Alice";

String greeting = STR."Hello, \{name}!";

You can also define your own processors—for example, to safely build SQL or JSON.

6. Structured Concurrency (2nd Preview) — JEP 462

This update brings minor refinements to structured concurrency, especially around task scope management and error propagation.

7. Stream Gatherers (Preview) — JEP 461

A powerful new addition to the Stream API, gatherers allow for custom reduction operations, beyond what Collectors offer.

For example:

Stream<String> stream = ...

var custom = stream.gather(Gatherers.windowFixed(3));

This opens up new ways to work with sliding windows, batching, grouping, and more.

✅ Summary Table

Feature	JEP	Status	Type
Foreign Function & Memory API	454	Final	API
Statements Before super()	447	Final	Language
String Templates	459	2nd Preview	Language/API
Structured Concurrency	462	2nd Preview	API
Unnamed Variables and Patterns	443	Preview	Language
Unnamed Classes and main()	456	2nd Preview	Language
Stream Gatherers	461	Preview	API

Should You Upgrade to Java 22?

Java 22 is a solid step forward, especially for developers interested in:

• Native interop using the finalized FFM API

• Cleaner constructor and pattern syntax

• Continued experimentation with Loom and Amber features

⚠️ Note: As a non-LTS release, Java 22 is not ideal for production environments that require long-term support. Java 21 (LTS) is the better choice unless you're actively experimenting or developing cutting-edge libraries.

Final Thoughts

Java 22 shows that the platform is not slowing down. The Java team continues to focus on expressiveness, performance, and modern developer experience.

Whether you’re working with native code, scaling apps with virtual threads, or crafting clean DSLs with string templates, Java 22 has something to offer.