diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 999bd73..e7edbf3 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -60,6 +60,7 @@
 LOCAL_INTERMEDIATE_SOURCE_DIR:=
 LOCAL_JAVACFLAGS:=
 LOCAL_JAVA_LIBRARIES:=
+LOCAL_JAVA_LAYERS_FILE:=
 LOCAL_NO_STANDARD_LIBRARIES:=
 LOCAL_CLASSPATH:=
 LOCAL_DROIDDOC_USE_STANDARD_DOCLET:=
diff --git a/core/definitions.mk b/core/definitions.mk
index beebc26..956ba62 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1466,6 +1466,8 @@
     \@$(PRIVATE_CLASS_INTERMEDIATES_DIR)/java-source-list-uniq \
     || ( rm -rf $(PRIVATE_CLASS_INTERMEDIATES_DIR) ; exit 41 ) \
 fi
+$(if $(PRIVATE_JAVA_LAYERS_FILE), $(hide) build/tools/java-layers.py \
+    $(PRIVATE_JAVA_LAYERS_FILE) \@$(PRIVATE_CLASS_INTERMEDIATES_DIR)/java-source-list-uniq,)
 $(hide) rm -f $(PRIVATE_CLASS_INTERMEDIATES_DIR)/java-source-list
 $(hide) rm -f $(PRIVATE_CLASS_INTERMEDIATES_DIR)/java-source-list-uniq
 $(if $(PRIVATE_JAR_EXCLUDE_FILES), $(hide) find $(PRIVATE_CLASS_INTERMEDIATES_DIR) \
diff --git a/core/java.mk b/core/java.mk
index 421ecf3..cc498af 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -254,6 +254,11 @@
 	$(hide) $(ACP) -fp $(PRIVATE_SOURCE_FILE) $@
 ALL_MODULES.$(LOCAL_MODULE).STUBS := $(full_classes_stubs_jar)
 
+# The layers file allows you to enforce a layering between java packages.
+# Run build/tools/java-layers.py for more details.
+layers_file := $(addprefix $(LOCAL_PATH)/, $(LOCAL_JAVA_LAYERS_FILE))
+$(full_classes_compiled_jar): PRIVATE_JAVA_LAYERS_FILE := $(layers_file)
+
 # Compile the java files to a .jar file.
 # This intentionally depends on java_sources, not all_java_sources.
 # Deps for generated source files must be handled separately,
@@ -261,8 +266,9 @@
 $(full_classes_compiled_jar): PRIVATE_JAVACFLAGS := $(LOCAL_JAVACFLAGS)
 $(full_classes_compiled_jar): PRIVATE_JAR_EXCLUDE_FILES := $(LOCAL_JAR_EXCLUDE_FILES)
 $(full_classes_compiled_jar): PRIVATE_DONT_DELETE_JAR_META_INF := $(LOCAL_DONT_DELETE_JAR_META_INF)
-$(full_classes_compiled_jar): $(java_sources) $(java_resource_sources) $(full_java_lib_deps) $(jar_manifest_file) \
-	$(RenderScript_file_stamp) $(proto_java_sources_file_stamp) $(LOCAL_ADDITIONAL_DEPENDENCIES)
+$(full_classes_compiled_jar): $(java_sources) $(java_resource_sources) $(full_java_lib_deps) \
+    $(jar_manifest_file) $(layers_file) \
+    $(RenderScript_file_stamp) $(proto_java_sources_file_stamp)
 	$(transform-java-to-classes.jar)
 
 # All of the rules after full_classes_compiled_jar are very unlikely