[7.0.0] Fix Java runtime toolchain resolution in cross-compilation scenarios

.bazelrc

@@ -14,6 +14,9 @@ build:remote_shared --tool_java_runtime_version=rbe_jdk
 build:remote_shared --noexperimental_check_desugar_deps
 
 # Configuration to build and test Bazel on RBE on Ubuntu 18.04 with Java 11
+# Workaround for https://github.com/bazelbuild/bazel/issues/19837.
+# TODO(bazel-team): Remove this toolchain when .bazelversion is 7.0.0rc2 or later.
+build:ubuntu2004_java11 --extra_toolchains=//:bazel_rbe_java_toolchain_definition
 build:ubuntu2004_java11 --extra_toolchains=@rbe_ubuntu2004_java11//java:all
 build:ubuntu2004_java11 --crosstool_top=@rbe_ubuntu2004_java11//cc:toolchain
 build:ubuntu2004_java11 --extra_toolchains=@rbe_ubuntu2004_java11//config:cc-toolchain
@@ -34,6 +37,9 @@ build:windows --extra_toolchains=@bazel_tools//tools/python:autodetecting_toolch
 
 build:windows_arm64 --platforms=//:windows_arm64
 build:windows_arm64 --extra_toolchains=@local_config_cc//:cc-toolchain-arm64_windows
+# When cross-compiling, the local Java runtime, which is used by default, will not be compatible
+# with the target.
+build:windows_arm64 --java_runtime_version=remotejdk_11
 
 # Enable Bzlmod
 common:bzlmod --enable_bzlmod

BUILD

@@ -1,6 +1,7 @@
 # Bazel - Google's Build System
 
 load("@bazel_skylib//rules:write_file.bzl", "write_file")
+load("@rules_java//toolchains:default_java_toolchain.bzl", "default_java_toolchain")
 load("@rules_license//rules:license.bzl", "license")
 load("@rules_pkg//pkg:tar.bzl", "pkg_tar")
 load("@rules_python//python:defs.bzl", "py_binary")
@@ -293,3 +294,19 @@ REMOTE_PLATFORMS = ("rbe_ubuntu2004_java11",)
     )
     for platform_name in REMOTE_PLATFORMS
 ]
+
+# Workaround for https://github.com/bazelbuild/bazel/issues/19837.
+# TODO(bazel-team): Remove these two targets when .bazelversion is 7.0.0rc2 or later.
+default_java_toolchain(
+    name = "bazel_java_toolchain",
+    bootclasspath = ["@rules_java//toolchains:platformclasspath"],
+    source_version = "11",
+    tags = ["manual"],
+    target_version = "11",
+)
+
+default_java_toolchain(
+    name = "bazel_rbe_java_toolchain",
+    source_version = "11",
+    target_version = "11",
+)

MODULE.bazel

@@ -24,7 +24,7 @@ bazel_dep(name = "zstd-jni", version = "1.5.2-3.bcr.1")
 bazel_dep(name = "blake3", version = "1.3.3.bcr.1")
 bazel_dep(name = "zlib", version = "1.3")
 bazel_dep(name = "rules_cc", version = "0.0.9")
-bazel_dep(name = "rules_java", version = "6.3.1")
+bazel_dep(name = "rules_java", version = "7.0.6")
 bazel_dep(name = "rules_proto", version = "5.3.0-21.7")
 bazel_dep(name = "rules_jvm_external", version = "5.2")
 bazel_dep(name = "rules_python", version = "0.24.0")
@@ -231,10 +231,10 @@ use_repo(
     "remotejdk17_macos_aarch64",
     "remotejdk17_win",
     "remotejdk17_win_arm64",
-    "remotejdk20_linux",
-    "remotejdk20_macos",
-    "remotejdk20_macos_aarch64",
-    "remotejdk20_win",
+    "remotejdk21_linux",
+    "remotejdk21_macos",
+    "remotejdk21_macos_aarch64",
+    "remotejdk21_win",
 )
 
 # =========================================
@@ -309,6 +309,10 @@ register_toolchains("@local_config_winsdk//:all")
 
 register_toolchains("//src/main/res:empty_rc_toolchain")
 
+# Workaround for https://github.com/bazelbuild/bazel/issues/19837.
+# TODO(bazel-team): Remove when .bazelversion is 7.0.0rc2 or later.
+register_toolchains("//:bazel_java_toolchain_definition")
+
 # =========================================
 # Android tools dependencies
 # =========================================

distdir_deps.bzl

@@ -106,17 +106,17 @@ DIST_DEPS = {
             "rules_java_builtin",
             "rules_java_builtin_for_testing",
         ],
-        "archive": "rules_java-6.3.1.tar.gz",
-        "sha256": "117a1227cdaf813a20a1bba78a9f2d8fb30841000c33e2f2d2a640bd224c9282",
-        "urls": ["https://github.com/bazelbuild/rules_java/releases/download/6.3.1/rules_java-6.3.1.tar.gz"],
+        "archive": "rules_java-7.0.6.tar.gz",
+        "sha256": "e81e9deaae0d9d99ef3dd5f6c1b32338447fe16d5564155531ea4eb7ef38854b",
+        "urls": ["https://github.com/bazelbuild/rules_java/releases/download/7.0.6/rules_java-7.0.6.tar.gz"],
         "workspace_file_content": "",
         "used_in": [
             "additional_distfiles",
         ],
         "license_kinds": [
             "@rules_license//licenses/spdx:Apache-2.0",
         ],
-        "package_version": "6.1.1",
+        "package_version": "7.0.6",
     },
     # Used in src/test/java/com/google/devtools/build/lib/blackbox/framework/blackbox.WORKSAPCE
     "rules_proto": {

src/BUILD

@@ -585,7 +585,7 @@ filegroup(
         "@rules_testing//:LICENSE",
     ] + [
         "@remotejdk%s_%s//:WORKSPACE" % (version, os)
-        for version in ("17", "20")
+        for version in ("17", "21")
         for os in ("macos", "macos_aarch64", "linux", "win")
     ] + ["@bazel_tools_repo_cache//:files"],
 )

src/MODULE.tools

@@ -1,10 +1,11 @@
 # NOTE: When editing this file, also update the lockfile.
 #   bazel run //src/test/tools/bzlmod:update_default_lock_file
+#   bazel mod deps --lockfile_mode=update
 
 module(name = "bazel_tools")
 
 bazel_dep(name = "rules_cc", version = "0.0.9")
-bazel_dep(name = "rules_java", version = "6.3.1")
+bazel_dep(name = "rules_java", version = "7.0.6")
 bazel_dep(name = "rules_license", version = "0.0.3")
 bazel_dep(name = "rules_proto", version = "4.0.0")
 bazel_dep(name = "rules_python", version = "0.4.0")

src/test/java/com/google/devtools/build/android/dexer/BUILD

@@ -28,7 +28,7 @@ java_library(
         ),
         "//conditions:default": ["NoAndroidSdkStubTest.java"],
     }),
-    javacopts = ["-source 7 -target 7"],  # we run this through dx for testing, so no lambdas!
+    javacopts = ["-source 8 -target 8"],
     resources = ["testresource.txt"],
     deps = [
         "//src/test/java/com/google/devtools/build/lib/testutil",

src/test/py/bazel/test_base.py

@@ -89,11 +89,11 @@ class TestBase(absltest.TestCase):
       'remotejdk17_macos_aarch64',
       'remotejdk17_win',
       'remotejdk17_win_arm64',
-      'remotejdk20_linux',
-      'remotejdk20_macos',
-      'remotejdk20_macos_aarch64',
-      'remotejdk20_win',
-      'remotejdk20_win_arm64',
+      'remotejdk21_linux',
+      'remotejdk21_macos',
+      'remotejdk21_macos_aarch64',
+      'remotejdk21_win',
+      'remotejdk21_win_arm64',
       'rules_cc',
       'rules_java',
       'rules_java_builtin_for_testing',

src/test/shell/bazel/bazel_java17_test.sh

@@ -173,11 +173,11 @@ EOF
   bazel build //pkg:Main \
     --extra_toolchains=//pkg:java_toolchain_definition \
     --java_language_version=17 \
-    --java_runtime_version=remotejdk_20 \
+    --java_runtime_version=remotejdk_21 \
     &>"${TEST_log}" && fail "Expected build to fail"
 
   expect_log "error: \[BazelJavaConfiguration\] The Java 17 runtime used to run javac is not " \
-    "recent enough to compile for the Java 20 runtime in external/remotejdk20_[a-z0-9]*\. Either " \
+    "recent enough to compile for the Java 21 runtime in external/remotejdk21_[a-z0-9]*\. Either " \
     "register a Java toolchain with a newer java_runtime or specify a lower " \
     "--java_runtime_version\."
 }
@@ -220,11 +220,11 @@ EOF
   bazel build //pkg:gen \
     --extra_toolchains=//pkg:java_toolchain_definition \
     --tool_java_language_version=17 \
-    --tool_java_runtime_version=remotejdk_20 \
+    --tool_java_runtime_version=remotejdk_21 \
     &>"${TEST_log}" && fail "Expected build to fail"
 
   expect_log "error: \[BazelJavaConfiguration\] The Java 17 runtime used to run javac is not " \
-    "recent enough to compile for the Java 20 runtime in external/remotejdk20_[a-z0-9]*\. Either " \
+    "recent enough to compile for the Java 21 runtime in external/remotejdk21_[a-z0-9]*\. Either " \
     "register a Java toolchain with a newer java_runtime or specify a lower " \
     "--tool_java_runtime_version\."
 }

src/test/shell/bazel/bazel_java_test_defaults.sh

@@ -306,6 +306,52 @@ EOF
     //pkg:foo_deploy.jar &>"$TEST_log" || fail "Build should succeed"
 }
 
+function test_java_library_compiles_for_any_platform_with_local_jdk() {
+  mkdir -p pkg
+  cat > pkg/BUILD.bazel <<'EOF'
+platform(name = "exotic_platform")
+java_library(
+  name = "foo",
+  srcs = ["Foo.java"],
+)
+EOF
+
+    cat > pkg/Foo.java <<'EOF'
+package com.example;
+public class Foo {
+  public static void main(String[] args) {
+    System.out.println("Hello World!");
+  }
+}
+EOF
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=local_jdk \
+    //pkg:foo &>"$TEST_log" || fail "Build should succeed"
+}
+
+function test_java_library_compiles_for_any_platform_with_remote_jdk() {
+  mkdir -p pkg
+  cat > pkg/BUILD.bazel <<'EOF'
+platform(name = "exotic_platform")
+java_library(
+  name = "foo",
+  srcs = ["Foo.java"],
+)
+EOF
+
+    cat > pkg/Foo.java <<'EOF'
+package com.example;
+public class Foo {
+  public static void main(String[] args) {
+    System.out.println("Hello World!");
+  }
+}
+EOF
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=remotejdk_11 \
+    //pkg:foo &>"$TEST_log" || fail "Build should succeed"
+}
+
 function test_non_executable_java_binary_compiles_for_any_platform_with_local_jdk() {
   mkdir -p pkg
   cat > pkg/BUILD.bazel <<'EOF'
@@ -332,4 +378,89 @@ EOF
     //pkg:foo_deploy.jar &>"$TEST_log" || fail "Build should succeed"
 }
 
+function test_non_executable_java_binary_compiles_for_any_platform_with_remote_jdk() {
+  mkdir -p pkg
+  cat > pkg/BUILD.bazel <<'EOF'
+platform(name = "exotic_platform")
+java_binary(
+  name = "foo",
+  srcs = ["Foo.java"],
+  create_executable = False,
+)
+EOF
+
+    cat > pkg/Foo.java <<'EOF'
+package com.example;
+public class Foo {
+  public static void main(String[] args) {
+    System.out.println("Hello World!");
+  }
+}
+EOF
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=remotejdk_11 \
+    //pkg:foo &>"$TEST_log" || fail "Build should succeed"
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=remotejdk_11 \
+    //pkg:foo_deploy.jar &>"$TEST_log" || fail "Build should succeed"
+}
+
+function test_executable_java_binary_fails_without_runtime_with_local_jdk() {
+  mkdir -p pkg
+  cat > pkg/BUILD.bazel <<'EOF'
+platform(name = "exotic_platform")
+java_binary(
+  name = "foo",
+  srcs = ["Foo.java"],
+  main_class = "com.example.Foo",
+)
+EOF
+
+    cat > pkg/Foo.java <<'EOF'
+package com.example;
+public class Foo {
+  public static void main(String[] args) {
+    System.out.println("Hello World!");
+  }
+}
+EOF
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=local_jdk \
+    //pkg:foo &>"$TEST_log" && fail "Build should fail"
+  expect_log "While resolving toolchains for target //pkg:foo ([0-9a-f]*): No matching toolchains found for types @bazel_tools//tools/jdk:runtime_toolchain_type"
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=local_jdk \
+    //pkg:foo_deploy.jar &>"$TEST_log" && fail "Build should fail"
+  expect_log "While resolving toolchains for target //pkg:foo_deployjars_internal_rule ([0-9a-f]*): No matching toolchains found for types @bazel_tools//tools/jdk:runtime_toolchain_type"
+}
+
+function test_executable_java_binary_fails_without_runtime_with_remote_jdk() {
+  mkdir -p pkg
+  cat > pkg/BUILD.bazel <<'EOF'
+platform(name = "exotic_platform")
+java_binary(
+  name = "foo",
+  srcs = ["Foo.java"],
+  main_class = "com.example.Foo",
+)
+EOF
+
+    cat > pkg/Foo.java <<'EOF'
+package com.example;
+public class Foo {
+  public static void main(String[] args) {
+    System.out.println("Hello World!");
+  }
+}
+EOF
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=remotejdk_11 \
+    //pkg:foo &>"$TEST_log" && fail "Build should fail"
+  expect_log "While resolving toolchains for target //pkg:foo ([0-9a-f]*): No matching toolchains found for types @bazel_tools//tools/jdk:runtime_toolchain_type"
+
+  bazel build --platforms=//pkg:exotic_platform --java_runtime_version=remotejdk_11 \
+    //pkg:foo_deploy.jar &>"$TEST_log" && fail "Build should fail"
+  expect_log "While resolving toolchains for target //pkg:foo_deployjars_internal_rule ([0-9a-f]*): No matching toolchains found for types @bazel_tools//tools/jdk:runtime_toolchain_type"
+}
+
 run_suite "Java toolchains tests, configured using flags or the default_java_toolchain macro."

src/test/shell/bazel/bazel_with_jdk_test.sh

@@ -92,9 +92,10 @@ function set_up() {
 
   mkdir -p java/main
   cat >java/main/BUILD <<EOF
-java_library(
+java_binary(
     name = 'JavaExample',
     srcs = ['JavaExample.java'],
+    main_class = 'JavaExample',
 )
 EOF