diff --git a/tests/core/dom/Android.mk b/tests/core/dom/Android.mk
index 10bb38a..69d4af3 100644
--- a/tests/core/dom/Android.mk
+++ b/tests/core/dom/Android.mk
@@ -29,4 +29,7 @@
 
 LOCAL_PACKAGE_NAME := android.core.tests.dom
 
+# for java.* javax.* support classes in libcore/support/src/test/java
+LOCAL_DX_FLAGS := --core-library
+
 include $(BUILD_CTSCORE_PACKAGE)
diff --git a/tests/core/xml/Android.mk b/tests/core/xml/Android.mk
index c798324..825d14e 100644
--- a/tests/core/xml/Android.mk
+++ b/tests/core/xml/Android.mk
@@ -30,4 +30,7 @@
 
 LOCAL_PACKAGE_NAME := android.core.tests.xml
 
+# for java.* javax.* support classes in libcore/support/src/test/java
+LOCAL_DX_FLAGS := --core-library
+
 include $(BUILD_CTSCORE_PACKAGE)