Add support for toolchain java 15

[Jonpez2]

Closes #11871

I modelled this on @davido's addition of a java 14 toolchain, here:https://github.com/bazelbuild/bazel/pull/11514.

The test plan has the same form:

Create java_tools from this commit:
$ bazel build src:java_tools_java11.zip

Switch to using the java_tools from the above step in WORKSPACE file:

  load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
  http_archive(
    name = "remote_java_tools_linux",
    urls = [
        "file:///<path to the java_tools_java11.zip>",
    ],
  )

Add Zulu OpenJDK15 to use as javabase in WORKSPACE file:

  http_archive(
    name = "openjdk15_linux_archive",
    build_file_content = """
java_runtime(name = 'runtime', srcs =  glob(['**']), visibility = ['//visibility:public'])
exports_files(["WORKSPACE"], visibility = ["//visibility:public"])
""",
    strip_prefix = "zulu15.27.17-ca-jdk15.0.0-linux_x64",
    urls = ["https://cdn.azul.com/zulu/bin/zulu15.27.17-ca-jdk15.0.0-linux_x64.tar.gz"],
  )

Activate custom java toolchain and javabase in .bazelrc file:

  build --java_toolchain=@remote_java_tools_linux//:toolchain_jdk_15
  build --host_java_toolchain=@remote_java_tools_linux//:toolchain_jdk_15
  build --javabase=@openjdk15_linux_archive//:runtime
  build --host_javabase=@openjdk15_linux_archive//:runtime

Create Java 15 example class file:

public class Javac15Example {
  static String textBlock = """
              Hello,
              World
              """;
  public static void main(String[] args) {
    System.out.println(textBlock);
  }
}

Add Bazel file to build Java 15 syntax class:

  java_binary(
    name = "Javac15Example",
    srcs = ["Javac15Example.java"],
    main_class = "Javac15Example",
  )

Test that it works as expected:

  $ bazel run java:Javac15Example
INFO: Analyzed target //java:Javac15Example (1 packages loaded, 2 targets configured).
INFO: Found 1 target...
INFO: From Building java/Javac15Example.jar (1 source file):
Target //java:Javac15Example up-to-date:
  bazel-bin/java/Javac15Example.jar
  bazel-bin/java/Javac15Example
INFO: Elapsed time: 1.502s, Critical Path: 1.30s
INFO: 1 process: 1 worker.
INFO: Build completed successfully, 2 total actions
INFO: Build completed successfully, 2 total actions
Hello,
World

[googlebot]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project (if not, look below for help). Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please visit https://cla.developers.google.com/ to sign.

Once you've signed (or fixed any issues), please reply here with @googlebot I signed it! and we'll verify it.

---

What to do if you already signed the CLA

Individual signers

• It's possible we don't have your GitHub username or you're using a different email address on your commit. Check your existing CLA data and verify that your email is set on your git commits.

Corporate signers

• Your company has a Point of Contact who decides which employees are authorized to participate. Ask your POC to be added to the group of authorized contributors. If you don't know who your Point of Contact is, direct the Google project maintainer to go/cla#troubleshoot (Public version).
• The email used to register you as an authorized contributor must be the email used for the Git commit. Check your existing CLA data and verify that your email is set on your git commits.
• The email used to register you as an authorized contributor must also be attached to your GitHub account.

ℹ️ Googlers: Go here for more info.

[Jonpez2]

@googlebot I signed it!

[googlebot]

CLAs look good, thanks!

ℹ️ Googlers: Go here for more info.

[davido]

Thanks for the PR. Can you check why CI is failing: [1]? The error is:

(09:53:10) ERROR: /workdir/src/BUILD:744:10: no such package '@remote_java_tools_javac15_test_windows//': The repository '@remote_java_tools_javac15_test_windows' could not be resolved and referenced by '//src:test_repos'.

https://buildkite.com/bazel/bazel-bazel-github-presubmit/builds/7032#fa4a0465-296c-4186-a234-6a72643b54d1

[davido]

I see some unrelated white space changes. I would rather revert them all, and only include additions related to java_toolchain_jdk15. Clean up changes should be done in their own PR. Just guessing: you have run buildifier on this files, that also changed the white spaces and shuffled around the attributes.

[Jonpez2]

Done

[davido]

@Jonpez2 Thanks for the PR.

Could you please reference this #11871 in the commit message?

//Cc @lberki @comius @philwo @meteorcloudy

Before this PR is merged we should upload Zulu JDK15 archives to bazel mirror.

[Jonpez2]

I fixed the specific error you highlighted, @davido , but I'm quite lost on the current set - I can reproduce the failure locally but the error message gives me no hints...

[comius]

Thanks @Jonpez2 for your effort! It seems that for one time we will catch up with Java releases.

[comius]

I uploaded zulu15 to bazel mirror.

[comius]

After this fix all the tests should pass.

[comius]

src/java_tools_java11.zip here

[Jonpez2]

Nice thank you, done.

[comius]

and "//src:java_tools_java11_zip" here...

tools 11 will have java 14 and java 15

[Jonpez2]

Nice thank you, done.

[comius]

Thanks!