Section 1.1: Unnamed Variables & Patterns — JEP 456

The introduction of JEP 456 focuses on unnamed variables and patterns, which improves the clarity of code when variable declarations or nested patterns are present but not utilized. Both are represented by an underscore character.

• Value: This feature clarifies the developer's intent with unused bindings or lambda parameters, reducing the risk of errors. It enhances code maintainability by highlighting variables that must be declared but remain unused, such as in catch clauses. Furthermore, it allows multiple patterns to be included in a single case label, provided they don’t declare any pattern variables. It also improves the readability of record patterns by eliminating unnecessary nested type patterns.

Section 1.2: Statements Before Super Calls — JEP 447

JEP 447 allows developers to include statements in constructors that do not reference the instance being created before an explicit constructor call.

• Value: This offers more flexibility in expressing constructor behavior, permitting more natural positioning of logic that would otherwise need to be placed in auxiliary static methods or intermediate constructors. It maintains the established guarantee that constructors execute in a top-down order during class instantiation, ensuring that subclass constructor code does not interfere with superclass instantiation.

This video titled "What's New in Java 22? A Comprehensive Overview" provides a detailed look at the key features and changes introduced in the latest release.

Section 1.3: String Templates (2nd Preview) — JEP 459

JEP 459 simplifies the process of writing Java programs by enabling the easy expression of strings with runtime-calculated values.

• Value: It enhances the readability of expressions that mix text and computations, whether the text is contained in a single source line or spans multiple lines. The feature also bolsters program security by supporting validation and transformation of templates and their embedded expression values, especially when constructing strings from user-provided values for other systems, like database queries.

The second video, "New Java Version 22 - The 3 Best New Features You'll ACTUALLY Use," outlines the most beneficial features developers can utilize.

Section 2.1: Implicitly Declared Classes and Instance Main Methods (2nd Preview) — JEP 463

JEP 463 allows students to write their initial Java programs without needing to grasp complex language features used in large-scale programming. Simplified declarations for single-class programs can be easily expanded as skills develop.

• Value: This enhances Java learning by providing a straightforward entry point into programming, allowing educators to gradually introduce concepts while enabling students to write concise basic programs.

Section 2.2: Foreign Function & Memory API — JEP 454

The Foreign Function and Memory API permits Java applications to interact with external code and data beyond the Java runtime.

• Value: It replaces fragile native methods and the Java Native Interface (JNI) with a clean, readable Java API, ensuring robust performance and wide platform support. The API enables safe invocation of native libraries and handling of native data without the common vulnerabilities associated with JNI.

Section 2.3: Class-File API (Preview) — JEP 457

JEP 457 introduces a standard API for parsing, generating, and transforming Java class files.

• Value: This allows frameworks and programs that rely on this API to quickly adapt to the latest class files in the newest JDK, facilitating the adoption of new language and VM features.

Section 2.4: Stream Gatherers (Preview) — JEP 461

JEP 461 enhances the Stream API to support custom intermediate operations, allowing for more flexible and expressive data transformations.

• Value: This boosts developer productivity and code readability by making common operations in streams more adaptable, allowing intermediate operations to manage streams of any size.

Section 2.5: Structured Concurrency (2nd Preview) — JEP 462

Structured concurrency simplifies concurrent programming by treating groups of related tasks running in different threads as a single unit.

• Value: This approach reduces typical risks associated with cancellation and shutdown, improving the reliability and observability of concurrent code.