Better handle of need_compile_java.

Change-Id: I609a27e2b35b08962243b6516c6c525c0c938d3c
diff --git a/core/package.mk b/core/package.mk
index ff202cb..fd72cce 100644
--- a/core/package.mk
+++ b/core/package.mk
@@ -480,3 +480,6 @@
 lintall : lint-$(LOCAL_PACKAGE_NAME)
 
 endif # skip_definition
+
+# Reset internal variables.
+all_res_assets :=