src/site/apt/examples/set-compiler-release.apt.vm

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 Setting the --release of the Java Compiler
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 Mahmoud Anouti
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 2019-12-20
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~~ NOTE: For help with the syntax of this file, see:
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Setting the <<<--release>>> of the Java Compiler

  Starting JDK 9, the <<<javac>>> executable can accept the <<<--release>>>
  option to specify against which Java SE release you want to build the project.
  For example, you have JDK 11 installed and used by Maven, but you want to
  build the project against Java 8.
  The <<<--release>>> option ensures that the code is compiled following the
  rules of the programming language of the specified release, and that generated
  classes target the release as well as the public API of that release. This
  means that, unlike the
  {{{../examples/set-compiler-source-and-target.html}<<<-source>>> and <<<-target>>> options}},
  the compiler will detect and generate an error when using APIs that don't exist
  in previous releases of Java SE.

  Since version 3.6 of the Compiler Plugin, this option can be provided either
  via a property:

+-----
<project>
  [...]
  <properties>
    <maven.compiler.release>8</maven.compiler.release>
  </properties>
  [...]
</project>
+-----

  or by configuring the plugin directly:

+-----
<project>
  [...]
  <build>
    [...]
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>${project.version}</version>
        <configuration>
          <release>8</release>
        </configuration>
      </plugin>
    </plugins>
    [...]
  </build>
  [...]
</project>
+-----

  <<Note:>> The value in the <<<release>>> parameter follows the new version naming scheme adopted
  since Java 9. As such, the release number does not start with 1.x anymore. Also note that the
  supported <<<release>>> targets include the release of the currently used JDK plus a limited number
  of previous releases.