Java5界から脱出した私のためのJava8紹介

What's New in JDK 8

Java Programming Language

• Lambda Expressions
  • lambda解禁
  • () -> {}
• Method references provide easy-to-read lambda expressions for methods that already have a name.
  • メソッドを参照渡しできる
  • HashSet::new
• Default methods enable new functionality to be added to the interfaces of libraries and ensure binary compatibility with code written for older versions of those interfaces.
  • interfaceにdefaultで使用される実装を書ける
• Method parameter reflection.
  • メソッドのパラメーター名を取得できる

Collections

• java.util.stream
  • map-reduce
• Performance Improvement for HashMaps with Key Collisions

Security

• Client-side TLS 1.2 enabled by default

Tools

• The jdeps command-line tool is provided for analyzing class files.
  • The new jdeps command-line tool allows the developer to analyze class files to determine package-level or class-level dependencies.

Internationalization

• Unicode 6.2.0

Scripting

• The Rhino javascript engine has been replaced with the Nashorn Javascript Engine

java.lang and java.util Packages

• Parallel Array Sorting
  • java.util.Arrays.parallelSort()

Java Date-Time Packages

• java.time
  • 日付、時刻、日付と時刻の組み合わせ、タイムゾーン、インスタント、期間、および時計のクラス。
• java.time.format
  • 日付と時刻をフォーマットおよび解析するためのクラス。

java.util.Optional