% Explanation of start of release changes

Overview

The start of release changes, the changes that turn JDK N into JDK (N+1), are primarily small updates to various files along with new files to store symbol information to allow javac --release N ... to run on JDK (N+1).

The updates include changes to files holding meta-data about the release, files under the src directory for API and tooling updates, and incidental updates under the test directory.

Details and file updates

As a matter of policy, there are a number of semantically distinct concepts which get incremented separately at the start of a new release:

  • Feature value of Runtime.version()
  • Highest source version modeled by javax.lang.model.SourceVersion
  • Highest class file format major version recognized by the platform
  • Highest -source/-target/--release argument recognized by javac and related tools

The expected file updates are listed below. Additional files may need to be updated for a particular release.

Meta-data files

  • jcheck/conf: update meta-data used by jcheck and the Skara tooling
  • make/conf/version-numbers.conf: update to meta-data used in the build

src files

  • src/hotspot/share/classfile/classFileParser.cpp: add a #define for the new version
  • src/java.base/share/classes/java/lang/classfile/ClassFile.java: add a constant for the new class file format version
  • src/java.base/share/classes/java/lang/reflect/ClassFileFormatVersion.java: add an enum constant for the new class file format version
  • src/java.compiler/share/classes/javax/lang/model/SourceVersion.java: add an enum constant for the new source version
  • src/java.compiler/share/classes/javax/lang/model/util/* visitors: Update @SupportedSourceVersion annotations to latest value. Note this update is done in lieu of introducing another set of visitors for each Java SE release.
  • src/jdk.compiler/share/classes/com/sun/tools/javac/code/Source.java: add an enum constant for the new source version internal to javac
  • src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassFile.java: add an enum constant for the new class file format version internal to javac
  • src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Target.java: add an enum constant for the new target version internal to javac
  • src/jdk.compiler/share/classes/com/sun/tools/javac/processing/PrintingProcessor.java update printing processor to support the new source version
  • The symbol information for --release is stored as new text files in the src/jdk.compiler/share/data/symbols directory, one file per module. The README file in that directory contains directions on how to create the files.

test files

  • test/langtools/tools/javac/api/TestGetSourceVersions.java: add new SourceVersion constant to test matrix.
  • test/langtools/tools/javac/classfiles/ClassVersionChecker.java: add new enum constant for the new class file version
  • test/langtools/tools/javac/lib/JavacTestingAbstractProcessor.java update annotation processor extended by javac tests to cover the new source version
  • test/langtools/tools/javac/preview/classReaderTest/Client.nopreview.out and test/langtools/tools/javac/preview/classReaderTest/Client.preview.out: update expected messages for preview errors and warnings