Java-9's full-fledged version is yet to be released but here I am going to discuss about its main developer features with reference to Early Access Build of JDK-9 and Java Magazine that I got from Oracle in my email last night around 11 PM NPT.
I will be explaining each feature with code examples where applicable and also provide implementation demo available at Github Repo.
Though the primary bone of JDK-9 is supposed to be JPMS( Java Platform Modular System), I am not going to mention it here as it's yet to be finalized by Java community.
NOTE: if you are IntelliJ IDEA user, FYI, IDEA version lower than 17 doesn't support Java 9.
Nine Hot features inside of JDK-9 for Java hard-cores
1) Factory Methods for Collections See example: java-stuffs/java9_features/src/main/java/Java9Collections.java 2) Optional Class Enhancement See example: java-stuffs/java9_features/src/main/java/OptionalClass.java 3) Stream API Enhancement 4) New tool: Read-Eval-Print-Loop(REPL) - JShell Try: $JAVA_HOME/bin/jshell 5) Concurrency Updates Java 7 added fork/join, java 8 added parallel streams, and now here java 9 has added publish-subscribe model to streams 6) Milling Project Coin Private methods can be added to interfaces single underscore is no longer valid as variable name, in Jdk-10 it will be used as lambda variable 7) Spin-Wait-Hints New method onSpinWait() has been added to Thread, supports optimization in JVM and Processor 8)Variable Handles 9) Process API Updates In addition to Process and ProcessBuilder, jdk9 introduces new interface ProcessHandle interface. This new interface is used to make a UNIX-style pipe line of Process Builders. TODO: JPMS Reference: Java 9 Magazine July/August issue.