Akom's Tech Ruminations

I'm testing a product that needs to be compiled with JDK 8 but tested (sometimes) on JDK 11. This is now possible to do with maven surefire (although that took some effort). With gradle, I was doing it as follows, which is terrible, even if the path comes from configuration:

// The old way:
test {
    executable = '/some/hardcoded/path/to/java'
}
 

Now that Gradle 6.7+ has built-in toolchains support, it's trivial to configure the compile toolchain:

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(11)
    }
}
 

But what about tests? What if I want to test with a different JVM? It's a little more verbose:

test {
    JavaToolchainService javaToolchainService = project.getExtensions().getByType(JavaToolchainService.class)
    def launcher = javaToolchainService.launcherFor{
        languageVersion = JavaLanguageVersion.of(11)
    }
    javaLauncher = launcher
    environment 'JAVA_HOME', launcher.get().metadata.installationPath //if your tests care about JAVA_HOME
}