This commit adds support for the following two JVM system properties
that control the Gradle build for alternative JDKs (i.e., a JDK other
than the one used to launch the Gradle process).
- customJavaHome: absolute path to the alternate JDK installation to
use to compile Java code and execute tests. Setting this system
property causes Groovy 3.0 RC3 to be used instead of 2.5.x. This
system property is also used in spring-oxm.gradle to determine
whether JiBX is supported.
- customJavaSourceVersion: Java version supplied to the `--release`
command line flag to control the Java source and target compatibility
version. Supported versions include 9 or higher. Do not set this
system property if Java 8 should be used.
Examples:
./gradlew -DcustomJavaHome=/opt/java/jdk-14 test
./gradlew --no-build-cache -DcustomJavaHome=/opt/java/jdk-14 test
./gradlew -DcustomJavaHome=/opt/java/jdk-14 -DcustomJavaSourceVersion=14 test
See gh-24474