Enable a nixpkgs imported Java runtime

We use JDK 8 because the nixpkgs version 18.09 does not provide Java 11
yet and Java 9 and 10 cause problems with Bazel 4.0.0 and are no longer
supported releases. See
- bazelbuild/bazel#8750 (comment)
- bazelbuild/bazel#13065

.bazelrc

@@ -1,11 +1,17 @@
 build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host
+
 build --crosstool_top=@nixpkgs_config_cc//:toolchain
 # Using toolchain resolution can lead to spurious dependencies on
 # `@local_config_cc//:builtin_include_directory_paths`. This needs to be
 # resolved before `--incompatible_enable_cc_toolchain_resolution` can be
 # recommended for `nixpkgs_cc_configure_hermetic`.
 # build --incompatible_enable_cc_toolchain_resolution
 
+build --javabase=@nixpkgs_java_runtime//:runtime
+build --host_javabase=@nixpkgs_java_runtime//:runtime
+build --java_toolchain=@bazel_tools//tools/jdk:toolchain_hostjdk8
+build --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_hostjdk8
+
 # CI Configuration
 # ----------------
 common:ci --color=no

WORKSPACE

@@ -8,6 +8,7 @@ rules_nixpkgs_dependencies()
 load(
     "//nixpkgs:nixpkgs.bzl",
     "nixpkgs_cc_configure",
+    "nixpkgs_java_configure",
     "nixpkgs_git_repository",
     "nixpkgs_local_repository",
     "nixpkgs_package",
@@ -185,6 +186,15 @@ nixpkgs_cc_configure(
     repository = "@remote_nixpkgs",
 )
 
+load("@rules_java//java:repositories.bzl", "rules_java_dependencies")
+
+rules_java_dependencies()
+
+nixpkgs_java_configure(
+    attribute_path = "jdk8.home",
+    repository = "@remote_nixpkgs",
+)
+
 nixpkgs_python_configure(
     python2_attribute_path = "python2",
     repository = "@remote_nixpkgs",