Java SE 9
Java Platform, Standard Edition 9 is a major feature release. The following summarizes features and enhancements in Java SE 9 and in JDK 9, Oracle’s implementation of Java SE 9.
A JDK Enhancement Proposal (JEP) is a proposal to design and implement a nontrivial change to the JDK.
Java Platform Module System
Introduces a new optional phase, link time, which is in-between compile time and run time, during which a set of modules can be assembled and optimized into a custom runtime image.
Adds options to the tools,
java where you can specify module paths, which locate definitions of modules.
Introduces the modular JAR file, which is a JAR file with a
module-info.class file in its root directory.
Introduces the JMOD format, which is a packaging format similar to JAR except it can include native code and configuration files; see the
Removes the endorsed-standards override mechanism and the extension mechanism.
tools.jar from the Java runtime image.