Java new features

Java 8 (LTS)

Introduction of functional programming
Functional Interfaces
- Consumer
- BiConsumer
- Supplier
- Function
- BiFunction
- Predicate
- BiPredicate
Interface
- default method
- static method
Stream API
- stream()
- parallelStream()
- filter()
- map()
- forEach()
- collect()
  - Collectors
    - toList()
    - toMap()
    - toSet()
    - groupingBy()
    - mapping()
    - joining()
Lambda Functions
Enhancements in Date/Time API
StringJoiner
String
- join()

Java 9

private method inside Interface
effective final with try-with-resource -> resource as dependency can be passed as an argument in try(resource). No need to say try(Resource resource = new Resource)
variable with name underscore ( _ ) not allowed now
String
- chars()
- codePoints()
Stream
- takeWhile(Predicate) -> It is like door open now and close in future
- dropWhile(Predicate) -> It is like door close now and open in future
IntStream iterate()
- with bounds
- without bounds
Optional
- ifPresentOrElse() -> It is new method to get Optional value
- or()
- stream()
Collectors
- filtering()
- flatMapping()
CompletableFuture
- completeOnTimeout()
- orTimeout()
List.of(), Set.of(), Map.of() methods to create immutable collections
Annonymous inner class with diamond <> operator
JShell -> REPL(Read Evaluate Print Loop) for java
JPMS (Java Platform Module System)
- Types of modules
  - unnamed modules
  - automatic modules
  - named modules
- jdeps
- jmods
- Modular Jar
- Module Path
- Module Declaration (module-info.java)
  - module (modulename){}
  - requires [static] [transitive] (module)
  - exports (package) [to] [module]
  - opens (package) [to] [module]
  - open module (moduelname) {}
  - provides (service) with (implementation)
  - uses (service)
- Module Descriptor (module-info.class)
- jdeps -jdkinternals [jar] (command to validate java internal api usage in jar)
Java Linker
- jlink

Java 10

local variable type inference using var
- var can't be used as method parameter and return type.
- var can't be used as class level attributes
- null can't be assigned to var
Optional
- orElseThrow()
Collectors
- toUnmodifiableList()
- toUnmodifiableSet()
- toUnmodifiableMap()
List.copyOf(), Set.copyOf() and Map.copyOf() methods

Java 11 (LTS)

var for lambda local variables
Optional.empty()
Files
- readString(Path)
- writeString(Path)
Predicate
- not()
String
- repeat(int) - Repeats the String as many times as provided by the int parameter
- lines() - Uses a Spliterator to lazily provide lines from the source string
- isBlank() - Indicates if the String is empty or contains only white space characters
- stripLeading() - Removes the white space from the beginning
- stripTrailing() - Removes the white space from the end
- strip() - Removes the white space from both, beginning and the end of string
  - Difference between trim() and strip()? - https://stackoverflow.com/questions/51266582/difference-between-string-trim-and-strip-methods-in-java-11

Java 12

Switch Expressions (Preview)
Collectors
- teeing()
String
- indent()
- transform()

Java 13

Text Block (Preview)
- multi line strings with """ --------- """
- No need to escape
- Smart Indentations
- Trailing space handling
- New escapes
  - \
  - \s
- formating
  - replace(), replaceAll()
  - String.format()
Switch Expressions (Second Preview)

Java 14

Switch Expressions (Live)
Java Records (Preview)
- data classes
- By default record is final and all properties are final (Immutable)
- Implements interfaces but can't extends classes
- No default constructor
- no setter method available
- toString() method avaialble by default
- Adding a canonical constructors
- Adding methods
- Adding local records inside function
Pattern Matching for instanceof (Preview)
Helpful NullPointerExceptions (-XX:+ShowCodeDetailsInExceptionMessages)
Text Block (Second Preview)

Java 15

Text Block (Live)
Sealed classes (Preview)
Local Class, Interface, Enum and Record (Preview)
Pattern Matching for instanceOf (Second Preview)
Java Records (Second Preview)
- We can use annotations on top of Record
- We can implement sealed interface

Java 16

Java Records (Live)
Add InvocationHandler::invokeDefault Method for Proxy's Default Method Support
Stream.toList()
Pattern Matching for instanceOf (Live)
Sealed classes (Second Preview)
Find Period-of-day using DateTimeFormatter.ofPattern("B").format(LocalDateTime.now())

Java 17 (LTS)

Pattern Matching for switch expressions (Preview)
Sealed classes (Live)
Strognly Encapsulate JDK Internals
Removal of experimental Java based ahead-of-time (AOT) and just-in-time (JIT) compiler.
Deprecate the Security Manager for removal

Java 18

UTF-8 by default in all java apis
Code Snippets in Java Documentation
- {@snippet : final SnippetExample instance = SnippetExample.newInstance(); // @highlight substring="newInstance" instance.processIt(); }
Minimal web server
- jwebserver
- Supports only HTTP protocol
- Serve only static contents
- Serve static content from specific folder
Pattern Matching for switch expressions (Second Preview)
- Guarded Pattern
- Null matching
Deprecate the finalization for removal

Java 19

Pattern Matching for switch expressions (Third Preview)

switch (obj) {
case String s && s.length() > 5 -> System.out.println(s.toUpperCase());
case String s                   -> System.out.println(s.toLowerCase());

case Integer i                  -> System.out.println(i * i);

default -> {}
}

above code can be written like this

switch (obj) {
case String s when s.length() > 5 -> System.out.println(s.toUpperCase());
case String s                     -> System.out.println(s.toLowerCase());

case Integer i                    -> System.out.println(i * i);

default -> {}
}

Record Patterns (Preview)
Virtual Threads (Preview)

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java-new-features's Introduction

Java new features

Java 8 (LTS)

Java 9

Java 10

Java 11 (LTS)

Java 12

Java 13

Java 14

Java 15

Java 16

Java 17 (LTS)

Java 18

Java 19

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