Coursier does not use embedded JDK

[MikhailTymchukFT]

Description of the problem / feature request:

When there is no local JDK installed, running $ bazel run @maven//:pin fails with the following message:

INFO: Repository maven instantiated at:
  no stack (--record_rule_instantiation_callstack not enabled)
Repository rule coursier_fetch defined at:
  /private/var/tmp/_bazel_mikhailtymchuk/b9e5d63d3710c48dc7e8e425579b45fb/external/rules_jvm_external/coursier.bzl:798:33: in <toplevel>
INFO: Repository 'maven' used the following cache hits instead of downloading the corresponding file.
 * Hash '6598d9277705ad8369a4f9c64217fbc31c19234f2cbcca9b1e5c4300a3abb317' for https://github.com/coursier/coursier/releases/download/v2.0.0-RC5-3/coursier.jar
If the definition of 'maven' was updated, verify that the hashes were also updated.
ERROR: An error occurred during the fetch of repository 'maven':
   Unable to run coursier: No Java runtime present, requesting install.
ERROR: Unable to run coursier: No Java runtime present, requesting install.
INFO: Elapsed time: 0.347s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (0 packages loaded)
FAILED: Build did NOT complete successfully (0 packages loaded)

Feature requests: what underlying problem are you trying to solve with this feature?

I'm trying to create maven_install.json file on a host without JDK.
I expect bazel uses embedded JDK (because it cannot use JDK provided as --host_javabase - it's too late, coursier already needs JDK at this moment).

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Complete example can be found here: https://github.com/MikhailTymchukFT/bazel-coursier-java-home-bug

WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

RULES_JVM_EXTERNAL_TAG = "3.2"
RULES_JVM_EXTERNAL_SHA = "82262ff4223c5fda6fb7ff8bd63db8131b51b413d26eb49e3131037e79e324af"

http_archive(
    name = "rules_jvm_external",
    sha256 = RULES_JVM_EXTERNAL_SHA,
    strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
    url = "https://github.com/bazelbuild/rules_jvm_external/archive/%s.zip" % RULES_JVM_EXTERNAL_TAG,
)

load("@rules_jvm_external//:defs.bzl", "maven_install")

maven_install(
    artifacts = [
        "junit:junit:4.12"
    ],
    fetch_sources = True,
    repositories = [
        "http://uk.maven.org/maven2",
        "https://jcenter.bintray.com/",
    ],
)

http_archive(
    name = "openjdk8u202_darwin_archive",
    build_file_content = """
package(default_visibility = ["//visibility:public"])

java_runtime(
    name = 'runtime',
    srcs =  glob(['**']),
    java='//:Contents/Home/bin/java',
    java_home='abc'
)
""",
    sha256 = "059f7c18faa6722aa636bbd79bcdff3aee6a6da5b34940b072ea6e3af85bbe1d",
    strip_prefix = "jdk8u202-b08",
    urls = ["https://github.com/AdoptOpenJDK/openjdk8-binaries/releases/download/jdk8u202-b08/OpenJDK8U-jdk_x64_mac_hotspot_8u202b08.tar.gz"],
)

What operating system are you running Bazel on?

MacOS 10.15.6

What's the output of bazel info release?

release 3.4.1

Have you found anything relevant by searching the web?

Found a similar issue: bazelbuild/bazel#6993
However, there is no coursier-related problems there.

[jin]

Thanks for the report. Please file rules_jvm_external issues on https://github.com/bazelbuild/rules_jvm_external.

Closing this as a duplicate of #445