Complete List of Features introduced from java version 8 to 21

Java 8 Features:

1. Lambda Expressions: Enables functional programming by allowing the creation of anonymous functions.
2. Stream API: Provides a fluent API for processing collections of data in a functional style.
3. Functional Interfaces: Interfaces with a single abstract method, used for lambda expressions.
4. Default Methods: Allows interfaces to have method implementations.
5. Method References: Provides a shorthand syntax for referencing methods.
6. Optional: A container object that may or may not contain a non-null value.
7. CompletableFuture: A Future that can be explicitly completed or chained together asynchronously.
8. New Date and Time API: java.time package for handling date and time operations in a more comprehensive and thread-safe manner.

Java 9 Features:

1. Modularization (Project Jigsaw): Introduces the Java Platform Module System (JPMS) for creating modular applications.
2. JShell: Provides an interactive command-line tool for evaluating Java expressions and statements.
3. Private Methods in Interfaces: Allows the declaration of private methods within interfaces.
4. Compact Strings: Optimizes memory usage for strings containing only ASCII characters.
5. HTTP/2 Client: Standardizes an HTTP client API that supports HTTP/2 and WebSocket.
6. Process API Updates: Enhances the Process API to control and manage native processes.
7. Improved Stream API: Adds several new methods to the Stream API for more efficient and concise stream processing.

Java 10 Features:

1. Local Variable Type Inference (var): Allows the type of local variables to be inferred from the context.
2. Optional.orElseThrow(): Adds a method to Optional for throwing an exception if the value is not present.
3. Collection.toArray(IntFunction): Enables creating arrays with a specified generator function.
4. Application Class-Data Sharing (CDS): Improves startup time and reduces memory footprint by sharing class metadata across JVM instances.
5. Thread-Local Handshakes: Provides a more efficient alternative to ThreadLocal variables.
6. Experimental JIT Compiler: Introduces an experimental just-in-time (JIT) compiler, Graal, for improved performance.

Java 11 Features:

1. HTTP Client (Standard): Introduces a standardized HTTP client API to replace HttpURLConnection.
2. Local-Variable Syntax for Lambda Parameters: Allows the use of var in lambda expression parameters.
3. String Methods:
   • String.lines(): Splits a string into lines.
   • String.repeat(int): Repeats a string a specified number of times.
   • String.strip(), String.stripLeading(), String.stripTrailing(): Removes leading/trailing whitespace.
4. Nest-Based Access Control: Introduces nest-based access controls to support private members access between nested classes.
5. Epsilon Garbage Collector (Experimental): Introduces a no-op garbage collector for performance testing and memory-only workloads.

Java 12 Features:

1. Switch Expressions (Preview): Extends the switch statement to support expressions.
2. JVM Constants API (Preview): Introduces an API to model nominal descriptions of key class-file and run-time artifacts.
3. Compact Number Formatting: Adds support for compact number formatting.
4. String Methods:
   • String.indent(int): Indents each line of the string by a specified number of spaces.
   • String.transform(Function): Applies a function to the string.
5. Improved Files.mismatch() Method: Adds an overload to Files.mismatch() method for better performance.
6. Microbenchmark Suite: Introduces a microbenchmark suite, java.microbench, for performance testing.

Java 13 Features:

1. Switch Expressions (Standard): Makes switch expressions a standard feature (not preview) and adds enhancements.
2. Text Blocks (Preview): Introduces a new syntax for multi-line string literals (preview feature).
3. Dynamic CDS Archives: Enhances the CDS feature to enable dynamic archiving of classes at runtime.
4. Reimplement the Legacy Socket API: Reimplements the underlying network protocol support for the legacy Socket API.
5. ZGC (Experimental): Introduces Z Garbage Collector (ZGC) as an experimental feature.
6. FileSystems.newFileSystem(): Adds a method to create a new file system.

Java 14 Features:

1. Records (Preview): Introduces record classes to provide a compact syntax for declaring classes that are transparent holders for shallowly immutable data.
2. Switch Expressions (Enhanced): Enhances switch expressions with additional features.
3. Pattern Matching for instanceof (Preview): Introduces pattern matching for the instanceof operator (preview feature).
4. NVM Express (NVMe) Support: Adds support for Non-Volatile Memory Express (NVMe) with HotSpot.

Java 15 Features:

1. Sealed Classes (Preview): Introduces sealed classes and interfaces to restrict which classes can extend or implement them (preview feature).
2. Text Blocks (Standard): Makes text blocks a standard feature (not preview) and adds enhancements.
3. Hidden Classes: Adds support for creating hidden classes that cannot be accessed by normal reflection.

Java 16 Features:

1. Records (Standard): Makes records a standard feature (not preview) and adds enhancements.
2. Pattern Matching for instanceof (Standard): Makes pattern matching for instanceof a standard feature (not preview).
3. Foreign-Memory Access API (Incubator): Introduces an API for accessing foreign memory outside the Java heap (incubator feature).

Java 17 Features:

1. Sealed Classes (Standard): Makes sealed classes and interfaces a standard feature (not preview) and adds enhancements.
2. Pattern Matching for Switch (Standard): Introduces pattern matching for switch expressions as a standard feature (not preview).
3. Strong Encapsulation of JDK Internals: Enhances the encapsulation of JDK internals to improve security and maintainability.

Java 18 Features:

1. Records (Enhancements): Further enhancements to records, including additional methods, serialization support, and customization options.
2. Pattern Matching for null: Introduces pattern matching for null to simplify null-checking code.
3. Enhanced Foreign-Memory Access API (Incubator): Improvements to the foreign-memory access API, including better performance and usability.
4. Vector API (Incubator): Introduces a vector API for performing vectorized operations on arrays and data sets.
5. Improved Pattern Matching (Enhanced): Enhancements to pattern matching syntax and functionality for better expressiveness and flexibility.
6. Enhanced JFR (Java Flight Recorder): Improvements to Java Flight Recorder for better performance profiling and monitoring capabilities.
7. Stream API Enhancements: Additional methods and optimizations to the Stream API for improved usability and performance.
8. Enhanced Switch Expressions: Further enhancements to switch expressions, including additional features and optimizations.
9. Enhanced Optional API: Improvements to the Optional class, including additional methods and utility functions.
10. Records (Standardization): Records are now standardized as a core feature of the Java language, providing a concise and immutable way to model data.
11. Pattern Matching (Standardization): Pattern matching features, including instanceof, switch expressions, and null patterns, are now standardized in the Java language.
12. Deprecation and Removals: Deprecation of outdated or redundant features and removal of deprecated APIs and functionalities to streamline the language.

Java 19 Features:

1. Deprecation and Removals: Continued deprecation and removal of outdated features, APIs, and functionalities to maintain a clean and modern codebase.
2. Enhanced Vector API: Further improvements and optimizations to the vector API for better performance and usability.
3. Enhanced Pattern Matching: Additional enhancements to pattern matching syntax and functionality based on community feedback and usage.
4. Improved JVM Performance: Performance optimizations and enhancements to the Java Virtual Machine (JVM) for better overall performance and efficiency.
5. Enhanced JFR: Continued improvements and optimizations to Java Flight Recorder for advanced performance monitoring and profiling.
6. Language Syntax Enhancements: Syntax improvements and refinements to the Java language for better readability and expressiveness.
7. Standard Library Enhancements: Additions and improvements to the standard Java library for enhanced functionality and usability.
8. Enhanced IDE Support: Improvements to IDE support for Java development, including better code completion, refactoring tools, and debugging capabilities.
9. API Updates: Updates and enhancements to various Java APIs for improved functionality, performance, and usability.
10. Security Enhancements: Improvements to Java security features and protocols to address emerging threats and vulnerabilities.

Java 20 Features:

1. Enhanced Vector API: Further refinements and optimizations to the vector API for improved performance and usability.
2. Enhanced Pattern Matching: Continued enhancements to pattern matching syntax and functionality based on community feedback and usage.
3. Improved JVM Performance: Additional optimizations and enhancements to the Java Virtual Machine (JVM) for better overall performance and efficiency.
4. Standard Library Updates: Updates and additions to the standard Java library to provide new functionality and improve existing features.
5. Language Syntax Refinements: Further refinements to the Java language syntax for better readability and expressiveness.
6. API Enhancements: Enhancements and updates to various Java APIs to improve functionality, performance, and usability.
7. Security Updates: Updates to Java security features and protocols to address security vulnerabilities and emerging threats.
8. IDE Integration: Improved integration with integrated development environments (IDEs) for enhanced developer productivity and ease of use.
9. Performance Monitoring Tools: Enhancements to performance monitoring tools and utilities for better insights into Java applications’ performance.
10. Compatibility Improvements: Improvements to ensure backward and forward compatibility with existing Java applications and libraries.

Java 21 Features:

1. Record Enhancements: Further enhancements to record classes, including support for non-final fields and custom serialization.
2. Pattern Matching for switch (Standardization): Pattern matching for switch expressions is now standardized as a core feature of the Java language.
3. Enhanced Vector API: Continuation of enhancements to the vector API for improved performance and usability.
4. Enhanced Pattern Matching: Additional refinements and optimizations to pattern matching syntax and functionality.
5. Standard Library Updates: Updates and additions to the standard Java library for enhanced functionality and usability.
6. Language Syntax Refinements: Further refinements to the Java language syntax for better readability and expressiveness.
7. API Enhancements: Improvements and updates to various Java APIs to improve functionality, performance, and usability.
8. Security Updates: Updates to Java security features and protocols to address security vulnerabilities and emerging threats.
9. IDE Integration: Enhanced integration with integrated development environments (IDEs) for improved developer productivity.
10. Performance Monitoring Tools: Enhancements to performance monitoring tools and utilities for better insights into Java applications’ performance.