Add option to use JDK from remote repository instead of the embedded JDK as default host javabase.

src/conditions/BUILD.tools

@@ -10,6 +10,12 @@ config_setting(
     visibility = ["//visibility:public"],
 )
 
+config_setting(
+    name = "linux_x86_64",
+    values = {"cpu": "k8"},
+    visibility = ["//visibility:public"],
+)
+
 config_setting(
     name = "linux_aarch64",
     values = {"cpu": "aarch64"},

src/main/java/com/google/devtools/build/lib/bazel/rules/java/jdk.WORKSPACE

@@ -82,3 +82,51 @@ bind(
     name = "jdk-default",
     actual = "@local_jdk//:jdk",
 )
+
+# OpenJDK distributions that should only be downloaded on demand (e.g. when
+# building a java_library or a genrule that uses java make variables).
+# This will allow us to stop bundling the full JDK with Bazel.
+# Note that while these are currently the same as the openjdk_* rules in
+# Bazel's WORKSPACE file, but they don't have to be the same.
+new_http_archive(
+    name = "remotejdk_linux",
+    sha256 = "f27cb933de4f9e7fe9a703486cf44c84bc8e9f138be0c270c9e5716a32367e87",
+    urls = [
+        "https://mirror.bazel.build/openjdk/azul-zulu-9.0.7.1-jdk9.0.7/zulu9.0.7.1-jdk9.0.7-linux_x64-allmodules.tar.gz",
+    ],
+    build_file = __embedded_dir__ + "/jdk.BUILD",
+    strip_prefix = "zulu9.0.7.1-jdk9.0.7-linux_x64-allmodules",
+)
+
+new_http_archive(
+    name = "remotejdk_macos",
+    sha256 = "404e7058ff91f956612f47705efbee8e175a38b505fb1b52d8c1ea98718683de",
+    urls = [
+        "https://mirror.bazel.build/openjdk/azul-zulu-9.0.7.1-jdk9.0.7/zulu9.0.7.1-jdk9.0.7-macosx_x64-allmodules.tar.gz",
+    ],
+    build_file = __embedded_dir__ + "/jdk.BUILD",
+    strip_prefix = "zulu9.0.7.1-jdk9.0.7-macosx_x64-allmodules",
+)
+
+new_http_archive(
+    name = "remotejdk_win",
+    sha256 = "e738829017f107e7a7cd5069db979398ec3c3f03ef56122f89ba38e7374f63ed",
+    urls = [
+        "https://mirror.bazel.build/openjdk/azul-zulu-9.0.7.1-jdk9.0.7/zulu9.0.7.1-jdk9.0.7-win_x64-allmodules.zip",
+    ],
+    build_file = __embedded_dir__ + "/jdk.BUILD",
+    strip_prefix = "zulu9.0.7.1-jdk9.0.7-win_x64-allmodules",
+)
+
+# The source-code for this OpenJDK can be found at:
+# https://openjdk.linaro.org/releases/jdk9-src-1708.tar.xz
+new_http_archive(
+    name = "remotejdk_linux_aarch64",
+    sha256 = "72e7843902b0395e2d30e1e9ad2a5f05f36a4bc62529828bcbc698d54aec6022",
+    urls = [
+        # When you update this, also update the link to the source-code above.
+        "http://openjdk.linaro.org/releases/jdk9-server-release-1708.tar.xz",
+    ],
+    build_file = __embedded_dir__ + "/jdk.BUILD",
+    strip_prefix = "jdk9-server-release-1708",
+)

src/main/java/com/google/devtools/build/lib/rules/java/JavaOptions.java

@@ -107,7 +107,7 @@ public ImportDepsCheckingLevelConverter() {
 
   @Option(
       name = "host_javabase",
-      defaultValue = "@bazel_tools//tools/jdk:host_jdk",
+      defaultValue = "null",
       converter = LabelConverter.class,
       documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
       effectTags = {OptionEffectTag.UNKNOWN},
@@ -116,6 +116,19 @@ public ImportDepsCheckingLevelConverter() {
               + "tools during a build.")
   public Label hostJavaBase;
 
+  @Option(
+      name = "incompatible_use_remotejdk_as_host_javabase",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      effectTags = {OptionEffectTag.UNKNOWN},
+      metadataTags = {
+        OptionMetadataTag.INCOMPATIBLE_CHANGE,
+        OptionMetadataTag.TRIGGERED_BY_ALL_INCOMPATIBLE_CHANGES
+      },
+      help =
+      "If enabled, uses a JDK downloaded from a remote repository instead of the embedded JDK.")
+  public boolean useRemoteJdkAsHostJavaBase;
+
   @Option(
     name = "javacopt",
     allowMultiple = true,
@@ -597,11 +610,22 @@ public ImportDepsCheckingLevelConverter() {
               + "--java_header_compilation is enabled.")
   public boolean requireJavaToolchainHeaderCompilerDirect;
 
+  private Label getHostJavaBase() {
+    if (hostJavaBase == null) {
+      if (useRemoteJdkAsHostJavaBase) {
+        return Label.parseAbsoluteUnchecked("@bazel_tools//tools/jdk:remote_jdk");
+      } else {
+        return Label.parseAbsoluteUnchecked("@bazel_tools//tools/jdk:host_jdk");
+      }
+    }
+    return hostJavaBase;
+  }
+
   @Override
   public FragmentOptions getHost() {
     JavaOptions host = (JavaOptions) getDefault();
 
-    host.javaBase = hostJavaBase;
+    host.javaBase = getHostJavaBase();
     host.jvmOpts = ImmutableList.of("-XX:ErrorFile=/dev/stderr");
 
     host.javacOpts = hostJavacOpts;
@@ -640,7 +664,7 @@ public FragmentOptions getHost() {
   @Override
   public Map<String, Set<Label>> getDefaultsLabels() {
     Map<String, Set<Label>> result = new HashMap<>();
-    result.put("JDK", ImmutableSet.of(javaBase, hostJavaBase));
+    result.put("JDK", ImmutableSet.of(javaBase, getHostJavaBase()));
     result.put("JAVA_TOOLCHAIN", ImmutableSet.of(javaToolchain));
 
     return result;

src/test/shell/integration/bazel_java_test.sh

@@ -72,6 +72,15 @@ EOF
   # Note that this will change in the future but is the current state.
   bazel aquery --output=text //java:javalib >& $TEST_log
   expect_log "exec external/embedded_jdk/bin/java"
+
+  bazel aquery --output=text --incompatible_use_remotejdk_as_host_javabase \
+    //java:javalib >& $TEST_log
+  expect_log "exec external/remotejdk_.*/bin/java"
+
+  bazel aquery --output=text --host_javabase=//:host_javabase \
+    --incompatible_use_remotejdk_as_host_javabase //java:javalib >& $TEST_log
+  expect_log "exec .*foobar/bin/java"
+  expect_not_log "exec external/remotejdk_.*/bin/java"
 }
 
 function test_javabase() {
@@ -209,16 +218,34 @@ EOF
   expect_not_log "foo"
   expect_not_log "bar"
   expect_not_log "embedded_jdk"
+  expect_not_log "remotejdk"
 
   bazel cquery --implicit_deps 'deps(//:with_java)' >& $TEST_log
   expect_not_log "foo"
   expect_log "bar"
   expect_log "embedded_jdk"
+  expect_not_log "remotejdk"
 
   bazel cquery --implicit_deps 'deps(//:with_java)' --host_javabase=:foo_javabase >& $TEST_log
   expect_log "foo"
   expect_log "bar"
   expect_not_log "embedded_jdk"
+  expect_not_log "remotejdk"
+
+  bazel cquery --implicit_deps 'deps(//:with_java)' \
+    --incompatible_use_remotejdk_as_host_javabase >& $TEST_log
+  expect_not_log "foo"
+  expect_log "bar"
+  expect_not_log "embedded_jdk"
+  expect_log "remotejdk"
+
+  bazel cquery --implicit_deps 'deps(//:with_java)' \
+    --host_javabase=:foo_javabase \
+    --incompatible_use_remotejdk_as_host_javabase >& $TEST_log
+  expect_log "foo"
+  expect_log "bar"
+  expect_not_log "embedded_jdk"
+  expect_not_log "remotejdk"
 }
 
 run_suite "Tests of specifying custom server_javabase/host_javabase and javabase."

tools/jdk/BUILD

@@ -315,3 +315,18 @@ test_suite(
     tests = [":windows_tests"],
     visibility = ["//tools:__pkg__"],
 )
+
+# Replacement for the embedded JDK as host javabase.
+alias(
+    name = "remote_jdk",
+    actual = select({
+        "//src/conditions:darwin": "@remotejdk_macos//:jdk",
+        "//src/conditions:darwin_x86_64": "@remotejdk_macos//:jdk",
+        "//src/conditions:windows": "@remotejdk_win//:jdk",
+        "//src/conditions:linux_aarch64": "@remotejdk_linux_aarch64//:jdk",
+        "//src/conditions:linux_x86_64": "@remotejdk_linux//:jdk",
+        # Fall back to the local JDK on any other platform.
+        "//conditions:default": "@local_jdk//:jdk",
+    }),
+    visibility = ["//visibility:public"],
+)