diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index d9f3372..f48c35d 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -58,6 +58,7 @@
 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 683ae16..867575a 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1455,6 +1455,8 @@
     $(PRIVATE_JAVACFLAGS) \
     \@$(PRIVATE_CLASS_INTERMEDIATES_DIR)/java-source-list-uniq \
     || ( rm -rf $(PRIVATE_CLASS_INTERMEDIATES_DIR) ; exit 41 )
+$(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
 $(hide) jar $(if $(strip $(PRIVATE_JAR_MANIFEST)),-cfm,-cf) \
diff --git a/core/java.mk b/core/java.mk
index 1cde62b..0c51da3 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -238,13 +238,19 @@
 	$(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,
 # via deps on the target that generates the sources.
 $(full_classes_compiled_jar): PRIVATE_JAVACFLAGS := $(LOCAL_JAVACFLAGS)
-$(full_classes_compiled_jar): $(java_sources) $(java_resource_sources) $(full_java_lib_deps) $(jar_manifest_file) \
-	$(RenderScript_file_stamp) $(proto_java_sources_file_stamp)
+$(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