The following items describe changes to and information about this release. In some cases, the descriptions provide links to additional detailed information about an issue or a change. These Release Notes do not duplicate the descriptions of the new features and enhancements for Java SE 9 and JDK 9 provided by [JDK 9 Release Notes Enhancements](http://www-content.oracle.com/technetwork/java/javase/jdk-relnotes-index-2162236.html), [What’s New in JDK 9](http://docs.oracle.com/javase/9/whatsnew/toc.htm), and [JSR 379: Java SE 9: Annex 1](http://cr.openjdk.java.net/~iris/se/9/java-se-9-pr-spec-01/java-se-9-annex-1.html). You should be aware of that content as well as the items described in these release notes.

The descriptions below might also identify potential compatibility issues that you could encounter when migrating to JDK 9. The [Kinds of Compatibility](https://wiki.openjdk.java.net/display/csr/Kinds+of+Compatibility) page on the OpenJDK wiki identifies three types of potential compatibility issues for Java programs used in these descriptions:

Source: Source compatibility concerns translating Java source code into class files.

Binary: Binary compatibility is defined in The Java Language Specification as preserving the ability to link without error.

Behavioral: Behavioral compatibility includes the semantics of the code that is executed at runtime.

See the [Compatibility & Specification Review (CSR)](https://wiki.openjdk.java.net/display/csr/Main) page on the OpenJDK wiki for more information about compatibility as it relates to the JDK.

Note: See the [JDK 9 Migration Guide](http://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-7744EF96-5899-4FB2-B34E-86D49B2E89B6) for specific compatibility issues that you might encounter when using JDK 9.