Java All Versions And Features - which version should be used

Java 7

Sure, here are some of the new features and improvements in Java 7:

• Try-with-resources statement: The try-with-resources statement is a new statement that allows you to automatically close resources that are declared in a try block. This can help to prevent resource leaks.
• Diamond operator: The diamond operator (<>) is a new operator that can be used to simplify the syntax for creating generic instances.
• Underscores in numeric literals: Underscores can now be used in numeric literals to improve readability. For example, the number 1_000_000 can be written as 1_000_000.
• Binary literals: Binary literals can now be used to represent numbers in binary format. For example, the number 1010 can be written as 0b1010.
• Strings in switch statements: Strings can now be used in switch statements. This can make code more concise and readable.
• Multiple exception types in catch blocks: Multiple exception types can now be specified in a catch block. This can make code more concise and readable.
• Automatic resource management: The Java Virtual Machine (JVM) now automatically manages resources that are declared in a try block. This can help to prevent resource leaks.
• Updated security model: The security model in Java 7 has been updated to address a number of security vulnerabilities.
• Performance improvements: Java 7 includes a number of performance improvements, such as improved garbage collection performance.

Overall, Java 7 is a significant release that brings a number of new features and improvements to the Java programming language. These features make Java more powerful, efficient, and secure.

Java 8

Java 8 key features:

• lambda expressions;
• functional interfaces;
• Stream API;
• interface default and static methods;
• method references;
• Optional;
• Date Time API;
• Nashorn, JavaScript engine;
• IO enhancements;
• Concurrency enhancements;
• JDBC enhancements;

Java 8 is a major release of the Java programming language, released in March 2014. It includes a number of new features and improvements, including:

• Lambda expressions: Lambda expressions are a new way to write anonymous functions. They can be used to simplify code that would otherwise be written using anonymous inner classes.
• Method references: Method references are a new way to refer to methods without having to explicitly specify the object and method name.
• Default methods: Default methods are a new way to add new functionality to interfaces without breaking existing code.
• Stream API: The Stream API is a new API for performing operations on collections of data. It provides a more concise and expressive way to write code that performs common operations on collections, such as filtering, mapping, and reducing.
• Date and time API: The Date and time API is a new API for working with dates and times. It provides a more modern and comprehensive way to work with dates and times than the old Date and Calendar classes.
• Other improvements: Java 8 also includes a number of other improvements, such as:
  • Improved support for functional programming
  • New tools and libraries
  • Performance improvements

Overall, Java 8 is a significant release that provides a number of new features and improvements that make Java a more powerful and expressive language.

Here are some examples of how the new features can be used:

• Lambda expressions: Lambda expressions can be used to simplify code that would otherwise be written using anonymous inner classes. For example, the following code uses a lambda expression to sort a list of strings:

List<String> list = Arrays.asList("a", "b", "c");  
list.sort((a, b) -> a.compareTo(b));  

• Method references: Method references can be used to refer to methods without having to explicitly specify the object and method name. For example, the following code uses a method reference to print the length of a string:

System.out.println(String::length, "Hello, world!");  

• Default methods: Default methods are a new way to add new functionality to interfaces without breaking existing code. For example, the following code uses a default method to provide a default implementation of the equals() method:

interface Comparable<T> {  
  
 default boolean equals(T o) { return compareTo(o) == 0; }}  

• Stream API: The Stream API is a new API for performing operations on collections of data. It provides a more concise and expressive way to write code that performs common operations on collections, such as filtering, mapping, and reducing. For example, the following code uses the Stream API to find the average of the numbers in a list:

List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);  
double average = list.stream().mapToInt(Integer::intValue).average().getAsDouble();  

• Date and time API: The Date and time API is a new API for working with dates and times. It provides a more modern and comprehensive way to work with dates and times than the old Date and Calendar classes. For example, the following code uses the Date and time API to get the current date and time:

Instant now = Instant.now();  

These are just a few examples of how the new features in Java 8 can be used. For more information, please refer to the Java 8 documentation.

Java 9

• Modular System;
• New HTTP client;
• Process API;
• Try-With-Resources enhancements;
• Interface private method;
• String new storage implementation;

Java 9 is a major release of the Java programming language, released in September 2017. It includes a number of new features and improvements, including:

• Module System: The module system is a new way to organize and manage Java code. It provides a way to decouple code into independent modules, which can be reused and combined in different ways.
• JShell: JShell is a new interactive shell for Java. It allows you to experiment with Java code and explore the Java API.
• HTTP/2 Client: Java 9 includes a new HTTP/2 client. HTTP/2 is a new version of the HTTP protocol that provides significant performance improvements over HTTP/1.1.
• Multi-Resolution Image API: The Multi-Resolution Image API provides a way to work with images that have multiple resolutions. This can be useful for displaying images on devices with different screen sizes.
• Other improvements: Java 9 also includes a number of other improvements, such as:
  • Improved support for modular programming
  • New tools and libraries
  • Performance improvements

Here are some examples of how the new features can be used:

• Module System: The module system can be used to decouple code into independent modules, which can be reused and combined in different ways. For example, you could create a module for your application’s core logic, a module for your application’s UI, and a module for your application’s database access. This would make your application easier to maintain and update.
• JShell: JShell can be used to experiment with Java code and explore the Java API. For example, you could use JShell to try out new features in Java 9 or to learn about the Java API.
• HTTP/2 Client: The HTTP/2 client can be used to improve the performance of your web applications. For example, you could use the HTTP/2 client to make requests to a web server that supports HTTP/2. This would result in faster loading times for your web pages.
• Multi-Resolution Image API: The Multi-Resolution Image API can be used to display images on devices with different screen sizes. For example, you could use the Multi-Resolution Image API to display an image on a smartphone, a tablet, and a desktop computer. This would ensure that the image is displayed at the correct resolution on each device.

These are just a few examples of how the new features in Java 9 can be used. For more information, please refer to the Java 9 documentation.

Java 10

• Local Variable Type Interface;
• Unmodifiable Collections;

Java 10 is a minor release of the Java programming language, released in March 20, 2018. It includes a number of new features and improvements, including:

• Local-Variable Type Inference: Local-Variable Type Inference is a new feature that allows you to omit the type of a local variable if it can be inferred from the initializer expression. For example, the following code is equivalent:

int x = 10;  

var x = 10;  

• Immutability Collections: Java 10 adds a number of new immutable collections, including List.of(), Set.of(), and Map.of(). These collections are created with a fixed set of elements and cannot be modified after they are created.
• Optional.orElseThrow(): The Optional.orElseThrow() method allows you to provide a default value for an Optional object if it is empty. For example, the following code will throw an IllegalStateException if the Optional object is empty:

Optional<String> name = Optional.ofNullable("John Doe");  
System.out.println(name.get());  

Optional<String> name = Optional.ofNullable("");  
System.out.println(name.get()); // Throws an IllegalStateException  

The following code will print “John Doe” if the Optional object is not empty, or “Unknown” if it is empty:

Optional<String> name = Optional.ofNullable("John Doe");  
System.out.println(name.orElse("Unknown"));  

• Time-Based Release Versioning: Java 10 introduces a new release model called Time-Based Release Versioning (TBRV). Under TBRV, Java releases will be numbered according to the year and month in which they are released. For example, Java 10 was released in March 2018, so its version number is 10.0.1.

• Other improvements: Java 10 also includes a number of other improvements, such as:

  • Improved support for modular programming
  • New tools and libraries
  • Performance improvements

Overall, Java 10 is a significant release that provides a number of new features and improvements that make Java a more powerful and expressive language.

Here are some examples of how the new features can be used:

• Local-Variable Type Inference: Local-Variable Type Inference can be used to make your code more concise and readable. For example, the following code is more concise than the equivalent code that explicitly specifies the type of the local variable:

int x = 10;  
int y = 20;  

var x = 10;  
var y = 20;  

• Immutability Collections: Immutable collections can be used to make your code more thread-safe and easier to reason about. For example, the following code is thread-safe because the List object is immutable:

List<String> names = List.of("John Doe", "Jane Doe");  

The following code is not thread-safe because the List object is mutable:

List<String> names = new ArrayList<>();  
names.add("John Doe");  
names.add("Jane Doe");  

• Optional.orElseThrow(): The Optional.orElseThrow() method can be used to handle errors more gracefully. For example, the following code will throw an IllegalStateException if the Optional object is empty:

Optional<String> name = Optional.ofNullable("John Doe");  
System.out.println(name.get());  

Optional<String> name = Optional.ofNullable("");  
System.out.println(name.get()); // Throws an IllegalStateException  

The following code will print “John Doe” if the Optional object is not empty, or “Unknown” if it is empty:

Optional<String> name = Optional.ofNullable("John Doe");  
System.out.println(name.orElse("Unknown"));  

• Time-Based Release Versioning: TBRV makes it easier to keep track of Java releases. For example, you can easily tell that Java 10 was released in March 2018 by looking at its version number (10.0.1).

These are just a few examples of how the new features in Java 10 can be used. For more information, please refer to the Java 10 documentation.

Java 11

• new String methods;
• new File methods;
• Collection to an Array;
• Predicate.not() method;
• var keyword for variables;
• HTTP client becomes standard client;
• Run Java files;
• Dynamic Class-File Constants;

Java 11 is a major release of the Java programming language, released on September 21, 2018. It includes a number of new features and improvements, including:

• A new HTTP client API, which provides a more efficient and flexible way to make HTTP requests.
• A new var keyword, which can be used to declare local variables without specifying their type.
• A new repeat() method on the String class, which can be used to repeat a string a specified number of times.
• Support for Unicode 10, which includes over 137,000 new characters.
• A new garbage collector, ZGC, which is designed for low-latency applications.
• A number of other improvements, such as a new flight recorder for diagnosing performance problems.

Java 11 is a significant release that brings a number of new features and improvements to the Java programming language. These features make Java more powerful, efficient, and flexible, and they are sure to be welcomed by Java developers.

Here are some of the key features of Java 11 in more detail:

• New HTTP client API: The new HTTP client API provides a more efficient and flexible way to make HTTP requests. It supports both HTTP/1.1 and HTTP/2, and it can be used to make requests to both servlets and web services.
• New var keyword: The new var keyword can be used to declare local variables without specifying their type. This can make code more concise and easier to read.
• New repeat() method on the String class: The new repeat() method on the String class can be used to repeat a string a specified number of times. This can be useful for generating text, such as passwords or random strings.
• Support for Unicode 10: Java 11 supports Unicode 10, which includes over 137,000 new characters. This makes Java more capable of handling text in a wide variety of languages.
• New garbage collector, ZGC: ZGC is a new garbage collector that is designed for low-latency applications. It can reduce the pauses that are caused by garbage collection, which can improve the performance of these applications.
• Other improvements: Java 11 also includes a number of other improvements, such as a new flight recorder for diagnosing performance problems.

Java 12

• String new methods;
• new number formatter;
• new switch expressions;
• Pattern matching for instanceof;

Java 12 was released on March 19, 2019. It includes a number of new features and improvements, including:

• Switch expressions: Switch expressions are a new feature that allows you to write more concise and readable code when you need to switch on a value.
• Compact number formatting: Compact number formatting is a new feature that allows you to format numbers in a more compact way.
• Shenandoah garbage collector: Shenandoah is a new garbage collector that is designed to be more efficient and scalable than the current garbage collectors.
• Default CDS archives: Default CDS archives are a new feature that makes it easier to build Java applications that are more efficient and secure.
• Microbenchmark suite: The microbenchmark suite is a new tool that can be used to measure the performance of Java code.

Here are some of the key features of Java 12 in more detail:

• Switch expressions: Switch expressions are a new feature that allows you to write more concise and readable code when you need to switch on a value. For example, the following code:

int value = 5;  
  
switch (value) {  
 case 1: System.out.println("One"); break; case 2: System.out.println("Two"); break; case 3: System.out.println("Three"); break; default: System.out.println("Other"); break;}  

Can be written more concisely as follows:

int value = 5;  
  
System.out.println(switch (value) {  
 case 1 -> "One"; case 2 -> "Two"; case 3 -> "Three"; default -> "Other";});  

• Compact number formatting: Compact number formatting is a new feature that allows you to format numbers in a more compact way. For example, the following code:

System.out.println(String.format("The number is %d", 1234567890));  

Will print the following output:

The number is 123,456,789  

With compact number formatting, the same code would print the following output:

The number is 123M  

• Shenandoah garbage collector: Shenandoah is a new garbage collector that is designed to be more efficient and scalable than the current garbage collectors. Shenandoah is still under development, but it is available in Java 12 for experimental use.
• Default CDS archives: Default CDS archives are a new feature that makes it easier to build Java applications that are more efficient and secure. CDS archives are a way of storing class data that can be used to improve the performance of Java applications. In Java 12, default CDS archives are created automatically for all Java applications.
• Microbenchmark suite: The microbenchmark suite is a new tool that can be used to measure the performance of Java code. The microbenchmark suite is a collection of microbenchmarks that can be used to measure the performance of different aspects of Java code, such as the performance of different algorithms, the performance of different garbage collectors, and the performance of different libraries.

Java 13

• switch expressions with yield;

Java 13 was released on September 17, 2019. It includes a number of new features and improvements, including:

• Text blocks: Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Switch expressions: Switch expressions are a new feature that allows you to write more concise and readable code when you need to switch on a value. Switch expressions can be used to replace switch statements, and they offer a number of advantages, such as improved readability and conciseness.
• Reimplement the legacy Socket API: The legacy Socket API is a set of classes and interfaces that provide access to the underlying network sockets. The legacy Socket API has been deprecated in Java 9, and it will be removed in Java 17. Java 13 introduces a new implementation of the Socket API that is designed to be more efficient and secure.
• Dynamic CDS archives: Dynamic CDS archives are a new feature that makes it easier to build Java applications that are more efficient and secure. CDS archives are a way of storing class data that can be used to improve the performance of Java applications. In Java 13, dynamic CDS archives can be created on demand, which can improve the performance of Java applications that are frequently updated.
• Other improvements: Java 13 also includes a number of other improvements, such as:
  • Support for Unicode 12.1
  • New methods in the String class
  • New features in the Java API
  • Bug fixes

Java 14

• switch expressions standardized;
• Records for POJO;

Java 14 was released on March 17, 2020. It includes a number of new features and improvements, including:

• Switch expressions (standard): Switch expressions are a new feature that allows you to write more concise and readable code when you need to switch on a value. Switch expressions can be used to replace switch statements, and they offer a number of advantages, such as improved readability and conciseness.
• Pattern matching for instanceof (preview): Pattern matching for instanceof is a new feature that allows you to write more concise and readable code when you need to check the type of an object. Pattern matching for instanceof can be used to replace instanceof statements, and it offers a number of advantages, such as improved readability and conciseness.
• Records (preview): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.
• Text blocks (second preview): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Helpful NullPointerExceptions: Java 14 improves the usability of NullPointerException generated by the JVM by describing precisely which variable was null.
• Foreign-Memory Access API (Incubator): The Foreign-Memory Access API is a new API that allows Java programs to access foreign memory, such as native memory, outside the heap in a safe and efficient manner.

Java 15

Java 15 was released on September 16, 2020. It includes a number of new features and improvements, including:

• Sealed classes (preview): Sealed classes are a new feature that allows you to restrict the inheritance of a class. This can be used to prevent subclasses from being created that could break the invariants of the class.
• Pattern matching for instanceof (second preview): Pattern matching for instanceof is a new feature that allows you to write more concise and readable code when you need to check the type of an object. Pattern matching for instanceof can be used to replace instanceof statements, and it offers a number of advantages, such as improved readability and conciseness.
• Records (second preview): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.
• Text blocks (standard): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Hidden classes: Hidden classes are a new feature that allows you to create classes that are not visible to the public. This can be used to implement private APIs or to create classes that are only used by other classes in the same package.
• ZGC (experimental): ZGC is a new garbage collector that is designed to be low-pause and scalable. ZGC is still under development, but it is available in Java 15 for experimental use.
• Shenandoah (experimental): Shenandoah is a new garbage collector that is designed to be efficient and scalable. Shenandoah is still under development, but it is available in Java 15 for experimental use.
• Foreign-Memory Access API (second incubator): The Foreign-Memory Access API is a new API that allows Java programs to access foreign memory, such as native memory, outside the heap in a safe and efficient manner.
• Remove the Nashorn JavaScript Engine: The Nashorn JavaScript Engine is a JavaScript engine that was included in Java 8 and later. Nashorn has been deprecated since Java 11, and it has been removed in Java 15.
• Reimplement the Legacy DatagramSocket API: The legacy DatagramSocket API is a set of classes and interfaces that provide access to the underlying network sockets. The legacy DatagramSocket API has been deprecated in Java 9, and it will be removed in Java 17. Java 15 introduces a new implementation of the DatagramSocket API that is designed to be more efficient and secure.
• Disable and Deprecate Biased Locking: Biased locking is a feature of the Java memory model that is designed to improve the performance of lock contention. Biased locking has been deprecated since Java 11, and it has been disabled by default in Java 15.

Java 16

Java 16 was released on March 16, 2021. It includes a number of new features and improvements, including:

• Pattern matching for instanceof (final): Pattern matching for instanceof is a new feature that allows you to write more concise and readable code when you need to check the type of an object. Pattern matching for instanceof can be used to replace instanceof statements, and it offers a number of advantages, such as improved readability and conciseness.
• Records (final): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.
• Text blocks (second standard): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Vector API (incubator): The Vector API is a new API that allows Java programs to access vectors, which are arrays of primitive values. The Vector API is designed to be efficient and scalable.
• Migrate from Mercurial to Git + Migrate to GitHub: Java 16 marks the official transition of the Java codebase from Mercurial to Git. This will allow for greater collaboration and transparency within the Java community.
• Warnings for Value-Based Classes: Java 16 introduces a new warning that can be used to detect value-based classes. Value-based classes are classes that are immutable and have no non-final fields. The warning can be enabled by setting the -Xlint:value-based-class flag.
• Strongly Encapsulate JDK Internals by Default: Java 16 introduces a new default setting that strongly encapsulates JDK internals. This means that classes and interfaces that are not part of the public API will be inaccessible by default. The setting can be disabled by setting the -Djdk.internal.module.enableAccess=true flag.
• New Stream Methods: Java 16 introduces a number of new stream methods, including:
  • dropWhile(predicate): This method drops elements from the stream while the predicate returns true.
  • takeWhile(predicate): This method takes elements from the stream while the predicate returns true.
  • ofNullable(t): This method creates a stream from a single value, or an empty stream if the value is null.
• Packaging Tool: Java 16 introduces a new packaging tool that can be used to create self-contained Java archives. These archives can be used to deploy Java applications without the need for an installer.
• Performance Improvements: Java 16 includes a number of performance improvements, including:
  • Improved garbage collection performance
  • Improved startup performance
  • Improved memory usage

Java 17

Java 17 was released on September 14, 2021. It includes a number of new features and improvements, including:

• Pattern matching for instanceof (final): Pattern matching for instanceof is a new feature that allows you to write more concise and readable code when you need to check the type of an object. Pattern matching for instanceof can be used to replace instanceof statements, and it offers a number of advantages, such as improved readability and conciseness.

• Records (final): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.

• Text blocks (third standard): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.

• Vector API (incubator): The Vector API is a new API that allows Java programs to access vectors, which are arrays of primitive values. The Vector API is designed to be efficient and scalable.

• Migrate from Mercurial to Git + Migrate to GitHub: Java 17 marks the official transition of the Java codebase from Mercurial to Git. This will allow for greater collaboration and transparency within the Java community.

• Warnings for Value-Based Classes: Java 17 introduces a new warning that can be used to detect value-based classes. Value-based classes are classes that are immutable and have no non-final fields. The warning can be enabled by setting the -Xlint:value-based-class flag.

• Strongly Encapsulate JDK Internals by Default: Java 17 introduces a new default setting that strongly encapsulates JDK internals. This means that classes and interfaces that are not part of the public API will be inaccessible by default. The setting can be disabled by setting the -Djdk.internal.module.enableAccess=true flag.

• New Stream Methods: Java 17 introduces a number of new stream methods, including:

• dropWhile(predicate): This method drops elements from the stream while the predicate returns true.

• takeWhile(predicate): This method takes elements from the stream while the predicate returns true.

• ofNullable(t): This method creates a stream from a single value, or an empty stream if the value is null.

• Packaging Tool: Java 17 introduces a new packaging tool that can be used to create self-contained Java archives. These archives can be used to deploy Java applications without the need for an installer.

• Performance Improvements: Java 17 includes a number of performance improvements, including:

• Improved garbage collection performance

• Improved startup performance

• Improved memory usage

Java 18

Here are some of the new features and improvements in Java 18:

• Pattern matching for switch (second preview): Pattern matching for switch is a new feature that allows you to write more concise and readable code when you need to switch on a value. Pattern matching for switch can be used to replace switch statements, and it offers a number of advantages, such as improved readability and conciseness.
• Records (second preview): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.
• Text blocks (third preview): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Vector API (second incubator): The Vector API is a new API that allows Java programs to access vectors, which are arrays of primitive values. The Vector API is designed to be efficient and scalable.
• Internet-Address Resolution SPI (second incubator): The Internet-Address Resolution SPI is a new SPI that allows Java programs to resolve internet addresses. The SPI is designed to be flexible and extensible.
• Foreign Function & Memory API (second incubator): The Foreign Function & Memory API is a new API that allows Java programs to access foreign functions and memory, such as native memory, outside the heap in a safe and efficient manner.
• Deprecated Finalization for Removal: Finalization enables a callback invoked when any object is being treated and collected as garbage and has many issues. Removal of finalization will minimize garbage collection impact and will have a positive impact on potential performance.

Java 19

Java 19 was released on September 20, 2022. It includes a number of new features and improvements, including:

• Structured Concurrency (Incubator): Structured Concurrency is a new feature that allows you to write more concise and readable code when you need to manage concurrent tasks. Structured Concurrency can be used to replace traditional approaches to concurrency, such as using locks and threads, and it offers a number of advantages, such as improved readability and conciseness.
• Virtual Threads (Incubator): Virtual Threads are a new feature that allows you to create lightweight threads that are managed by the Java Virtual Machine (JVM). Virtual Threads can be used to improve the performance of concurrent applications, and they offer a number of advantages, such as improved scalability and reduced overhead.
• Pattern Matching for Switch (Third Preview): Pattern matching for switch is a new feature that allows you to write more concise and readable code when you need to switch on a value. Pattern matching for switch can be used to replace switch statements, and it offers a number of advantages, such as improved readability and conciseness.
• Records (Third Preview): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.
• Text blocks (Fourth Preview): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Vector API (Third Incubator): The Vector API is a new API that allows Java programs to access vectors, which are arrays of primitive values. The Vector API is designed to be efficient and scalable.
• Internet-Address Resolution SPI (Third Incubator): The Internet-Address Resolution SPI is a new SPI that allows Java programs to resolve internet addresses. The SPI is designed to be flexible and extensible.
• Foreign Function & Memory API (Third Incubator): The Foreign Function & Memory API is a new API that allows Java programs to access foreign functions and memory, such as native memory, outside the heap in a safe and efficient manner.
• Locale Class Constructors Deprecated: The Locale Class Constructors are deprecated in Java 19. This means that they will be removed in a future release of Java. Developers should use the new Locale.Builder class to create locales instead.
• ThreadGroup Degraded: The ThreadGroup class has been degraded in Java 19. This means that it is no longer recommended for use in new code. Developers should use the new ExecutorService class to manage threads instead.
• Remove Finalizer Implementation in SSLSocketImpl: The finalizer implementation in SSLSocketImpl has been removed in Java 19. This is because the finalizer was not being used and it was causing performance problems.

Java 20

Java 20 was released on March 21, 2023. It includes a number of new features and improvements, including:

• Pattern Matching for Switch (Final): Pattern matching for switch is a new feature that allows you to write more concise and readable code when you need to switch on a value. Pattern matching for switch can be used to replace switch statements, and it offers a number of advantages, such as improved readability and conciseness.
• Records (Final): Records are a new feature that allows you to create simple, immutable classes with a single constructor and automatically generated getters, setters, equals, hashCode, and toString methods. Records can be used to make your code more concise and readable.
• Text blocks (Fifth Preview): Text blocks are a new feature that allows you to write multiline strings more easily. Text blocks are enclosed in triple-double quotes, and they can contain line breaks, tabs, and other whitespace characters.
• Vector API (Fourth Incubator): The Vector API is a new API that allows Java programs to access vectors, which are arrays of primitive values. The Vector API is designed to be efficient and scalable.
• Internet-Address Resolution SPI (Fourth Incubator): The Internet-Address Resolution SPI is a new SPI that allows Java programs to resolve internet addresses. The SPI is designed to be flexible and extensible.
• Foreign Function & Memory API (Fourth Incubator): The Foreign Function & Memory API is a new API that allows Java programs to access foreign functions and memory, such as native memory, outside the heap in a safe and efficient manner.
• Sealed Classes (Second Preview): Sealed classes are a new feature that allows you to restrict the inheritance of a class. This can be used to prevent subclasses from being created that could break the invariants of the class.
• Preview Features (Second Preview): A number of preview features have been made available in Java 20, including:
  • Vector API
  • Internet-Address Resolution SPI
  • Foreign Function & Memory API
  • Sealed Classes
• Performance Improvements: Java 20 includes a number of performance improvements, including:
  • Improved garbage collection performance
  • Improved startup performance
  • Improved memory usage