chore: update runtime JDK to 21.0.8

... from the rules_java provided JDK 21.0.6.
This seems to be a pre-requesite for upgrading protobuf to > 26.0.

Author: simonresch

MODULE.bazel

@@ -420,6 +420,29 @@ REMOTE_JDK8 = [
     for jdk in REMOTE_JDK8
 ]
 
+# Use a more recent JDK 21 than is made available by rules_java.
+# This works around a test failure in the StressTest when updating protobuf to a
+# version > 26.0.
+# Remove after https://github.com/bazelbuild/rules_java/pull/328 has been merged/released.
+remote_jdk21_repos = use_extension("//third_party:jdk_21.bzl", "remote_jdk21_repos")
+
+REMOTE_JDK21 = [
+    "remote_jdk21_linux",
+    "remote_jdk21_macos",
+    "remote_jdk21_macos_aarch64",
+    "remote_jdk21_windows",
+]
+
+[
+    use_repo(remote_jdk21_repos, "{}_toolchain_config_repo".format(jdk))
+    for jdk in REMOTE_JDK21
+]
+
+[
+    register_toolchains("@{}_toolchain_config_repo//:all".format(jdk))
+    for jdk in REMOTE_JDK21
+]
+
 register_toolchains("//bazel/toolchains:kotlin_toolchain")
 
 # Used in CI.

third_party/jdk_21.bzl

@@ -0,0 +1,86 @@
+#
+# Copyright 2024 Code Intelligence GmbH
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+load("@rules_java//toolchains:remote_java_repository.bzl", "remote_java_repository")
+
+def _remote_jdk21_repos(_):
+    remote_java_repository(
+        name = "remote_jdk21_linux",
+        target_compatible_with = [
+            "@platforms//os:linux",
+            "@platforms//cpu:x86_64",
+        ],
+        sha256 = "63f56bbb46958cf57352fba08f2755e0953799195e5545acc0c8a92920beff1e",
+        strip_prefix = "zulu21.44.17-ca-jdk21.0.8-linux_x64",
+        urls = [
+            "https://cdn.azul.com/zulu/bin/zulu21.44.17-ca-jdk21.0.8-linux_x64.tar.gz",
+        ],
+        version = "21",
+    )
+    remote_java_repository(
+        name = "remote_jdk21_linux_aarch64",
+        target_compatible_with = [
+            "@platforms//os:linux",
+            "@platforms//cpu:aarch64",
+        ],
+        sha256 = "ff7f2edd1d5c153cb6cb493a3aa3523453e29a05ec513b25c24aa1477ec0c722",
+        strip_prefix = "zulu21.44.17-ca-jdk21.0.8-linux_aarch64",
+        urls = [
+            "https://cdn.azul.com/zulu/bin/zulu21.44.17-ca-jdk21.0.8-linux_aarch64.tar.gz",
+        ],
+        version = "21",
+    )
+    remote_java_repository(
+        name = "remote_jdk21_macos_aarch64",
+        target_compatible_with = [
+            "@platforms//os:macos",
+            "@platforms//cpu:aarch64",
+        ],
+        sha256 = "d22ce05fea3e3f28c8c59f2c348bc78ee967bf1289a4fb28796cc0177ff6c8db",
+        strip_prefix = "zulu21.44.17-ca-jdk21.0.8-macosx_aarch64",
+        urls = [
+            "https://cdn.azul.com/zulu/bin/zulu21.44.17-ca-jdk21.0.8-macosx_aarch64.tar.gz",
+        ],
+        version = "21",
+    )
+    remote_java_repository(
+        name = "remote_jdk21_macos",
+        target_compatible_with = [
+            "@platforms//os:macos",
+            "@platforms//cpu:x86_64",
+        ],
+        sha256 = "2af080500b5cc286a6353187c7c59b5aafcb3edc29c1c87d1fd71ba2d6a523f1",
+        strip_prefix = "zulu21.44.17-ca-jdk21.0.8-macosx_x64",
+        urls = [
+            "https://cdn.azul.com/zulu/bin/zulu21.44.17-ca-jdk21.0.8-macosx_x64.tar.gz",
+        ],
+        version = "21",
+    )
+    remote_java_repository(
+        name = "remote_jdk21_windows",
+        target_compatible_with = [
+            "@platforms//os:windows",
+            "@platforms//cpu:x86_64",
+        ],
+        sha256 = "f47dbd00384cb759f86a066be7545e467e5764f4653a237c32c07da96dc1c43b",
+        strip_prefix = "zulu21.44.17-ca-jdk21.0.8-win_x64",
+        urls = [
+            "https://cdn.azul.com/zulu/bin/zulu21.44.17-ca-jdk21.0.8-win_x64.zip",
+        ],
+        version = "21",
+    )
+
+remote_jdk21_repos = module_extension(_remote_jdk21_repos)