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)

References

• https://www.youtube.com/watch?v=oRcOiGWK9Ts
• https://www.youtube.com/watch?v=lBOwPYvdvLQ
• https://www.youtube.com/watch?v=jGuDzW85FPI&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=1
• https://www.youtube.com/watch?v=HeRZRGdvyL4&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=2
• https://www.youtube.com/watch?v=Xkb6QdljWhA&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=3
• https://www.youtube.com/watch?v=J1YKAFtNz70&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=9
• https://www.youtube.com/watch?v=FgGmnMq3UqE&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=15
• https://www.youtube.com/watch?v=cHmHrZZQWNc&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=16
• https://www.youtube.com/watch?v=JGZH_2Phy58&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=17
• https://www.youtube.com/watch?v=I7H8xaSBRIk&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=18
• https://www.youtube.com/watch?v=qBTBgSviBG4&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=31
• https://www.youtube.com/watch?v=22lDKofzkk0&list=PLEocw3gLFc8VHoA_OgHN1q6Zd-r-q-dvU&index=36
• https://www.youtube.com/watch?v=xzc8Hug0o5A
• https://www.youtube.com/watch?v=Yacu1yUktjY
• https://www.youtube.com/watch?v=Xkh5sa3vjTE
• https://www.youtube.com/watch?v=5GfE1-vEl1A