Avoids NullPointerException when running `bazel coverage //:xxx`, since PathFragment.getParentDirectory() may return null. Fixes #2212.

Also adds coverage-specific attributes to the java_binary rule.

--
PiperOrigin-RevId: 142516883
MOS_MIGRATED_REVID=142516883
diff --git a/tools/jdk/BUILD b/tools/jdk/BUILD
index 22d26eb..5b5596b 100644
--- a/tools/jdk/BUILD
+++ b/tools/jdk/BUILD
@@ -155,3 +155,14 @@
         ":proguard_whitelister",
     ],
 )
+
+# For java coverage
+alias(
+    name = "jacoco-blaze-agent",
+    actual = "//third_party/java/jacoco:blaze-agent",
+)
+
+alias(
+    name = "JacocoCoverage",
+    actual = "//src/java_tools/junitrunner/java/com/google/testing/coverage:JacocoCoverage",
+)