Java 8 to Java 11 - What are the new language features?

When you think about upgrading to Java 11 from Java 8 (e.g. from one LTS to the next), you might wonder about the new language features the new version provides. So here you find a list of all language features, which were added in Java 9, 10 and 11.

• Private methods in interfaces
  • Since we can use static and default methods in interfaces, it is sometimes useful to structure this code in private methods
• Local variable type inference (var keyword)
  • Can be used to add annotations to lambdas
• Factory methods for immutable collections
  • List.of(); -> creates an empty List
  • List.of("one", "two", "three");
  • Map.of(1, "one", 2, "two", 3, "three");
• New Stream methods
  • Stream#dropWhile(...)
  • Stream#takeWhile(...)
  • Stream#ofNullable(...)
• New Optional methods
  • Optional#orElseThrow() (no parameters) -> Does the same as Optional#get(), but the method name better describes, what happens, if no value is present.
  • Optional#ifPresentOrElse(...) -> Does the same as Optional#ifPresent, but you can define an action, if the value is not present
  • Optional#or(...) -> Returns an Optional with the result of the supplied lambda, if the original Optional is empty, otherwise an Optional with the original value
  • Optional#stream(...) -> Creates Stream containing the value of the Optional if present, otherwise an empty Stream
  • Optional#isEmpty()
• New String methods
  • String#isBlank()
  • String#lines() -> Splits the String into an Stream of Strings, separated by line breaks
  • String#repeat(int n)
  • String#strip() -> Removes all UTF-8 whitespace from the beginning and end of the String
  • String#stripLeading()
  • String#stripTrailing()
• New Files methods
  • Files.readString(...) -> Reads all file contens as UTF-8 into a String
  • Files.writeString(...) -> Writes a String into a file
• New Matcher methods (RegEx)
  • Matcher#appendReplacement(...) -> Can now also be used with StringBuilder instead of StringBuffer
  • Matcher#appendTail(...) -> Can now also be used with StringBuilder instead of StringBuffer
  • Matcher#replaceAll(...) -> The String can now be supplied with a Function
  • Matcher#replaceFirst(...) -> The String can now be supplied with a Function
  • Matcher#results(...) -> Returns a stream of the match results
• New CompletableFuture methods
  • CompletableFuture#orTimeout(...)
  • CompletableFuture#completeOnTimeout(...)
• @Deprecated gets two new parameters
  • boolean forRemoval -> “Indicates whether the annotated element is subject to removal in a future version.”
  • String since -> “The version in which the annotated element became deprecated.”