diff --git a/core/apidiff.mk b/core/apidiff.mk
new file mode 100644
index 000000000..330746900
--- /dev/null
+++ b/core/apidiff.mk
@@ -0,0 +1,177 @@
+#
+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##
+##
+## Common to both jdiff and javadoc
+##
+##
+
+LOCAL_IS_HOST_MODULE := $(call true-or-empty,$(LOCAL_IS_HOST_MODULE))
+ifeq ($(LOCAL_IS_HOST_MODULE),true)
+my_prefix := HOST_
+LOCAL_HOST_PREFIX :=
+else
+my_prefix := TARGET_
+endif
+
+LOCAL_MODULE_CLASS := $(strip $(LOCAL_MODULE_CLASS))
+ifndef LOCAL_MODULE_CLASS
+$(error $(LOCAL_PATH): LOCAL_MODULE_CLASS not defined)
+endif
+
+full_src_files := $(patsubst %,$(LOCAL_PATH)/%,$(LOCAL_SRC_FILES))
+out_dir := $(OUT_DOCS)/$(LOCAL_MODULE)/api_diff/current
+full_target := $(call doc-timestamp-for,$(LOCAL_MODULE)-diff)
+
+ifeq ($(LOCAL_IS_HOST_MODULE),true)
+$(full_target): PRIVATE_BOOTCLASSPATH :=
+full_java_libs := $(addprefix $(HOST_OUT_JAVA_LIBRARIES)/,\
+  $(addsuffix $(COMMON_JAVA_PACKAGE_SUFFIX),$(LOCAL_JAVA_LIBRARIES)))
+full_java_lib_deps := $(full_java_libs)
+
+else
+
+ifneq ($(LOCAL_SDK_VERSION),)
+  ifeq ($(LOCAL_SDK_VERSION)$(TARGET_BUILD_APPS),current)
+	# Use android_stubs_current if LOCAL_SDK_VERSION is current and no TARGET_BUILD_APPS.
+	LOCAL_JAVA_LIBRARIES := android_stubs_current $(LOCAL_JAVA_LIBRARIES)
+	$(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, android_stubs_current)
+  else ifeq ($(LOCAL_SDK_VERSION)$(TARGET_BUILD_APPS),system_current)
+	LOCAL_JAVA_LIBRARIES := android_system_stubs_current $(LOCAL_JAVA_LIBRARIES)
+	$(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, android_system_stubs_current)
+  else ifeq ($(LOCAL_SDK_VERSION)$(TARGET_BUILD_APPS),test_current)
+	LOCAL_JAVA_LIBRARIES := android_test_stubs_current $(LOCAL_JAVA_LIBRARIES)
+	$(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, android_test_stubs_current)
+  else
+	LOCAL_JAVA_LIBRARIES := sdk_v$(LOCAL_SDK_VERSION) $(LOCAL_JAVA_LIBRARIES)
+	$(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, sdk_v$(LOCAL_SDK_VERSION))
+  endif
+else
+  LOCAL_JAVA_LIBRARIES := core-oj core-libart ext framework $(LOCAL_JAVA_LIBRARIES)
+  $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, core-oj):$(call java-lib-files, core-libart)
+endif  # LOCAL_SDK_VERSION
+LOCAL_JAVA_LIBRARIES := $(sort $(LOCAL_JAVA_LIBRARIES))
+
+full_java_libs := $(call java-lib-files,$(LOCAL_JAVA_LIBRARIES)) $(LOCAL_CLASSPATH)
+full_java_lib_deps := $(call java-lib-deps,$(LOCAL_JAVA_LIBRARIES)) $(LOCAL_CLASSPATH)
+endif # !LOCAL_IS_HOST_MODULE
+
+$(full_target): PRIVATE_CLASSPATH := $(subst $(space),:,$(full_java_libs))
+$(full_target): PRIVATE_DOCLAVA_CLASSPATH := $(HOST_OUT_JAVA_LIBRARIES)/jsilver$(COMMON_JAVA_PACKAGE_SUFFIX):$(HOST_OUT_JAVA_LIBRARIES)/doclava$(COMMON_JAVA_PACKAGE_SUFFIX)
+
+intermediates.COMMON := $(call local-intermediates-dir,COMMON)
+
+$(full_target): PRIVATE_SOURCE_PATH := $(call normalize-path-list,$(LOCAL_DROIDDOC_SOURCE_PATH))
+$(full_target): PRIVATE_JAVA_FILES := $(filter %.java,$(full_src_files))
+$(full_target): PRIVATE_JAVA_FILES += $(addprefix $($(my_prefix)OUT_COMMON_INTERMEDIATES)/, $(filter %.java,$(LOCAL_INTERMEDIATE_SOURCES)))
+$(full_target): PRIVATE_SOURCE_INTERMEDIATES_DIR := $(intermediates.COMMON)/src
+$(full_target): PRIVATE_SRC_LIST_FILE := $(intermediates.COMMON)/droiddoc-src-list
+
+ifneq ($(strip $(LOCAL_ADDITIONAL_JAVA_DIR)),)
+$(full_target): PRIVATE_ADDITIONAL_JAVA_DIR := $(LOCAL_ADDITIONAL_JAVA_DIR)
+endif
+
+# Lists the input files for the doc build into a text file
+# suitable for the @ syntax of javadoc.
+# $(1): the file to create
+# $(2): files to include
+# $(3): list of directories to search for java files in
+define prepare-doc-source-list
+$(hide) mkdir -p $(dir $(1))
+$(call dump-words-to-file, $(2), $(1))
+$(hide) for d in $(3) ; do find $$d -name '*.java' -and -not -name '.*' >> $(1) 2> /dev/null ; done ; true
+endef
+
+##
+##
+## jdiff only
+##
+##
+
+jdiff := \
+	$(HOST_JDK_TOOLS_JAR) \
+	$(HOST_OUT_JAVA_LIBRARIES)/jdiff$(COMMON_JAVA_PACKAGE_SUFFIX)
+
+doclava := \
+	$(HOST_JDK_TOOLS_JAR) \
+	$(HOST_OUT_JAVA_LIBRARIES)/doclava$(COMMON_JAVA_PACKAGE_SUFFIX)
+
+$(full_target): PRIVATE_NEWAPI := $(LOCAL_APIDIFF_NEWAPI)
+$(full_target): PRIVATE_OLDAPI := $(LOCAL_APIDIFF_OLDAPI)
+$(full_target): PRIVATE_OUT_DIR := $(out_dir)
+$(full_target): PRIVATE_OUT_NEWAPI := $(out_dir)/current.xml
+$(full_target): PRIVATE_OUT_OLDAPI := $(out_dir)/$(notdir $(basename $(LOCAL_APIDIFF_OLDAPI))).xml
+$(full_target): PRIVATE_DOCLETPATH := $(HOST_OUT_JAVA_LIBRARIES)/jdiff$(COMMON_JAVA_PACKAGE_SUFFIX)
+$(full_target): \
+		$(full_src_files) \
+		$(full_java_lib_deps) \
+		$(jdiff) \
+		$(doclava) \
+		$(LOCAL_MODULE)-docs \
+		$(LOCAL_ADDITIONAL_DEPENDENCIES)
+	@echo Generating API diff: $(PRIVATE_OUT_DIR)
+	@echo   Old API: $(PRIVATE_OLDAPI)
+	@echo   New API: $(PRIVATE_NEWAPI)
+	@echo   Old XML: $(PRIVATE_OUT_OLDAPI)
+	@echo   New XML: $(PRIVATE_OUT_NEWAPI)
+	$(hide) mkdir -p $(dir $@)
+	@echo Converting API files to XML...
+	$(hide) mkdir -p $(PRIVATE_OUT_DIR)
+	$(hide) ( \
+		$(JAVA) \
+				$(addprefix -classpath ,$(PRIVATE_CLASSPATH):$(PRIVATE_DOCLAVA_CLASSPATH):$(PRIVATE_BOOTCLASSPATH):$(HOST_JDK_TOOLS_JAR)) \
+				com.google.doclava.apicheck.ApiCheck \
+				-convert2xml \
+					$(basename $(PRIVATE_NEWAPI)).txt \
+					$(basename $(PRIVATE_OUT_NEWAPI)).xml \
+	) || (rm -rf $(PRIVATE_OUT_DIR) $(PRIVATE_SRC_LIST_FILE); exit 45)
+	$(hide) ( \
+		$(JAVA) \
+				$(addprefix -classpath ,$(PRIVATE_CLASSPATH):$(PRIVATE_DOCLAVA_CLASSPATH):$(PRIVATE_BOOTCLASSPATH):$(HOST_JDK_TOOLS_JAR)) \
+				com.google.doclava.apicheck.ApiCheck \
+				-convert2xml \
+					$(basename $(PRIVATE_OLDAPI)).txt \
+					$(basename $(PRIVATE_OUT_OLDAPI)).xml \
+	) || (rm -rf $(PRIVATE_OUT_DIR) $(PRIVATE_SRC_LIST_FILE); exit 45)
+	@echo Running JDiff...
+	$(call prepare-doc-source-list,$(PRIVATE_SRC_LIST_FILE),$(PRIVATE_JAVA_FILES), \
+			$(PRIVATE_SOURCE_INTERMEDIATES_DIR) $(PRIVATE_ADDITIONAL_JAVA_DIR))
+	$(hide) ( \
+		$(JAVADOC) \
+				-encoding UTF-8 \
+				\@$(PRIVATE_SRC_LIST_FILE) \
+				-J-Xmx1600m \
+				-XDignore.symbol.file \
+				-quiet \
+				-doclet jdiff.JDiff \
+				-docletpath $(PRIVATE_DOCLETPATH) \
+				$(addprefix -bootclasspath ,$(PRIVATE_BOOTCLASSPATH)) \
+				$(addprefix -classpath ,$(PRIVATE_CLASSPATH)) \
+				-sourcepath $(PRIVATE_SOURCE_PATH)$(addprefix :,$(PRIVATE_CLASSPATH)) \
+				-d $(PRIVATE_OUT_DIR) \
+				-newapi $(notdir $(basename $(PRIVATE_OUT_NEWAPI))) \
+				-newapidir $(dir $(PRIVATE_OUT_NEWAPI)) \
+				-oldapi $(notdir $(basename $(PRIVATE_OUT_OLDAPI))) \
+				-oldapidir $(dir $(PRIVATE_OUT_OLDAPI)) \
+				-javadocnew ../../../reference/ \
+		&& touch -f $@ \
+	) || (rm -rf $(PRIVATE_OUT_DIR) $(PRIVATE_SRC_LIST_FILE); exit 45)
+
+ALL_DOCS += $(full_target)
+
+.PHONY: $(LOCAL_MODULE)-diff
+$(LOCAL_MODULE)-diff : $(full_target)
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 6ac260201..d2e7a6cad 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -14,6 +14,8 @@ LOCAL_AIDL_INCLUDES:=
 LOCAL_ALLOW_UNDEFINED_SYMBOLS:=
 LOCAL_ANNOTATION_PROCESSORS:=
 LOCAL_ANNOTATION_PROCESSOR_CLASSES:=
+LOCAL_APIDIFF_NEWAPI:=
+LOCAL_APIDIFF_OLDAPI:=
 LOCAL_APK_LIBRARIES:=
 LOCAL_ARM_MODE:=
 LOCAL_ASFLAGS:=
diff --git a/core/config.mk b/core/config.mk
index 80f74871b..c17b0f56f 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -112,6 +112,7 @@ BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
 BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
 BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
 BUILD_DROIDDOC:= $(BUILD_SYSTEM)/droiddoc.mk
+BUILD_APIDIFF:= $(BUILD_SYSTEM)/apidiff.mk
 BUILD_COPY_HEADERS := $(BUILD_SYSTEM)/copy_headers.mk
 BUILD_NATIVE_TEST := $(BUILD_SYSTEM)/native_test.mk
 BUILD_NATIVE_BENCHMARK := $(BUILD_SYSTEM)/native_benchmark.mk
diff --git a/core/tasks/apidiff.mk b/core/tasks/apidiff.mk
new file mode 100644
index 000000000..4eb59afbb
--- /dev/null
+++ b/core/tasks/apidiff.mk
@@ -0,0 +1,21 @@
+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# Rules for building API diffs.
+#
+
+.PHONY: api-diff
+
+api-diff: offline-sdk-referenceonly-diff