Fix a bug that allows to compile Tink for Java with Bazel 0.17.2 (lat…

…est).

Kokoro hasn't failed because its macOS and Ubuntu machines are using old Bazel versions.

Related issues:
#131
#136
bazelbuild/bazel#5997
bazelbuild/bazel#5594

PiperOrigin-RevId: 215787620
GitOrigin-RevId: 7b978f1374938e4b839f8357fc50d36b7ab96be5

docs/JAVA-HACKING.md

@@ -3,7 +3,6 @@
 ## Building Tink
 
 *   Install [Bazel](https://docs.bazel.build/versions/master/install.html).
-    Version 0.9.0 or newer are known to work correctly with Tink.
 
 *   To build Java, install Android SDK 23 or newer and set the ANDROID_HOME
     environment variable to the path of your Android SDK. On macOS, the SDK is

tools/javadoc.bzl

@@ -32,7 +32,7 @@ def _javadoc_library(ctx):
 
     include_packages = ":".join(ctx.attr.root_packages)
     javadoc_command = [
-        ctx.file._javadoc_binary.path,
+        "%s/bin/javadoc" % ctx.attr._jdk[java_common.JavaRuntimeInfo].java_home,
         "-sourcepath srcs",
         "-use",
         "-subpackages",
@@ -72,7 +72,8 @@ def _javadoc_library(ctx):
                 if path_prefix in src.path:
                     prepare_srcs_command += "cp %s srcs/%s && " % (src.path, path_prefix)
 
-    jar_command = "%s cf %s -C tmp ." % (ctx.file._jar_binary.path, ctx.outputs.jar.path)
+    jar_binary = "%s/bin/jar" % ctx.attr._jdk[java_common.JavaRuntimeInfo].java_home
+    jar_command = "%s cf %s -C tmp ." % (jar_binary, ctx.outputs.jar.path)
 
     ctx.actions.run_shell(
         inputs = srcs + classpath + ctx.files._jdk,
@@ -94,17 +95,10 @@ javadoc_library = rule(
             default = _android_jar,
             allow_single_file = True,
         ),
-        "_javadoc_binary": attr.label(
-            default = Label("@local_jdk//:bin/javadoc"),
-            allow_single_file = True,
-        ),
-        "_jar_binary": attr.label(
-            default = Label("@local_jdk//:bin/jar"),
-            allow_single_file = True,
-        ),
         "_jdk": attr.label(
-            default = Label("@local_jdk//:jdk-default"),
+            default = Label("@bazel_tools//tools/jdk:current_java_runtime"),
             allow_files = True,
+            providers = [java_common.JavaRuntimeInfo],
         ),
     },
     outputs = {"jar": "%{name}.jar"},