export Java variables to Bazel

Test: build/bazel/bp2build.sh
Change-Id: Ia06f9265c9f96e6add6edbd0cee925fe37b430d3
diff --git a/rules/soong_injection.bzl b/rules/soong_injection.bzl
index acbb5d9..9e2090e 100644
--- a/rules/soong_injection.bzl
+++ b/rules/soong_injection.bzl
@@ -20,6 +20,7 @@
     soong_injection_dir = build_dir + "/soong_injection"
     rctx.symlink(soong_injection_dir + "/mixed_builds", "mixed_builds")
     rctx.symlink(soong_injection_dir + "/cc_toolchain", "cc_toolchain")
+    rctx.symlink(soong_injection_dir + "/java_toolchain", "java_toolchain")
     rctx.symlink(soong_injection_dir + "/product_config", "product_config")
     rctx.symlink(soong_injection_dir + "/api_levels", "api_levels")
     rctx.symlink(soong_injection_dir + "/metrics", "metrics")