diff --git a/core/base_rules.mk b/core/base_rules.mk
index 548ed13..fbf9770 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -405,7 +405,7 @@
 #                 be up-to-date.
 ifdef LOCAL_IS_HOST_MODULE
 ifeq ($(USE_CORE_LIB_BOOTCLASSPATH),true)
-$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH := -bootclasspath $(call java-lib-deps,core-hostdex,$(LOCAL_IS_HOST_MODULE))
+$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH := -bootclasspath $(call java-lib-deps,core-libart-hostdex,$(LOCAL_IS_HOST_MODULE))
 
 full_shared_java_libs := $(call java-lib-files,$(LOCAL_JAVA_LIBRARIES),$(LOCAL_IS_HOST_MODULE))
 full_java_lib_deps := $(call java-lib-deps,$(LOCAL_JAVA_LIBRARIES),$(LOCAL_IS_HOST_MODULE))
diff --git a/core/config.mk b/core/config.mk
index 6067f9f..64dc68e 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -532,7 +532,7 @@
 
 # allow overriding default Java libraries on a per-target basis
 ifeq ($(TARGET_DEFAULT_JAVA_LIBRARIES),)
-  TARGET_DEFAULT_JAVA_LIBRARIES := core core-junit ext framework framework2
+  TARGET_DEFAULT_JAVA_LIBRARIES := core-libart core-junit ext framework framework2
 endif
 
 TARGET_CPU_SMP ?= true
diff --git a/core/droiddoc.mk b/core/droiddoc.mk
index 2a9cfc6..ea5c2f2 100644
--- a/core/droiddoc.mk
+++ b/core/droiddoc.mk
@@ -65,8 +65,8 @@
     $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, sdk_v$(LOCAL_SDK_VERSION))
   endif
 else
-  LOCAL_JAVA_LIBRARIES := core ext framework framework2 $(LOCAL_JAVA_LIBRARIES)
-  $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, core)
+  LOCAL_JAVA_LIBRARIES := core-libart ext framework framework2 $(LOCAL_JAVA_LIBRARIES)
+  $(full_target): PRIVATE_BOOTCLASSPATH := $(call java-lib-files, core-libart)
 endif  # LOCAL_SDK_VERSION
 LOCAL_JAVA_LIBRARIES := $(sort $(LOCAL_JAVA_LIBRARIES))
 
diff --git a/core/executable_prefer_symlink.mk b/core/executable_prefer_symlink.mk
index 2f04d0d..fa49e40 100644
--- a/core/executable_prefer_symlink.mk
+++ b/core/executable_prefer_symlink.mk
@@ -10,9 +10,20 @@
 # check because 32 bit targets may not define TARGET_PREFER_32_BIT_APPS
 # et al. since those variables make no sense in that context.
 ifeq ($(TARGET_IS_64_BIT),true)
-ifneq ($(TARGET_PREFER_32_BIT_APPS),true)
+ifeq ($(TARGET_SUPPORTS_64_BIT_APPS)|$(TARGET_SUPPORTS_32_BIT_APPS),true|true)
+  # We support both 32 and 64 bit apps, so we will have to
+  # base our decision on whether the target prefers one or the
+  # other.
+  ifneq ($(TARGET_PREFER_32_BIT_APPS),true)
+    $(my_symlink): PRIVATE_SRC_BINARY_NAME := $(LOCAL_MODULE_STEM_32)
+  else
+    $(my_symlink): PRIVATE_SRC_BINARY_NAME := $(LOCAL_MODULE_STEM_64)
+  endif
+else ifeq ($(TARGET_SUPPORTS_64_BIT_APPS),true)
+  # We support only 64 bit apps.
   $(my_symlink): PRIVATE_SRC_BINARY_NAME := $(LOCAL_MODULE_STEM_64)
 else
+  # We support only 32 bit apps.
   $(my_symlink): PRIVATE_SRC_BINARY_NAME := $(LOCAL_MODULE_STEM_32)
 endif
 else
diff --git a/core/host_dalvik_java_library.mk b/core/host_dalvik_java_library.mk
index 5024086..61eb3ff 100644
--- a/core/host_dalvik_java_library.mk
+++ b/core/host_dalvik_java_library.mk
@@ -27,7 +27,7 @@
 #######################################
 
 ifneq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
-  LOCAL_JAVA_LIBRARIES +=  core-hostdex
+  LOCAL_JAVA_LIBRARIES +=  core-libart-hostdex
 endif
 
 full_classes_compiled_jar := $(intermediates.COMMON)/classes-full-debug.jar
diff --git a/core/host_dalvik_static_java_library.mk b/core/host_dalvik_static_java_library.mk
index 05c4b16..3ae74e4 100644
--- a/core/host_dalvik_static_java_library.mk
+++ b/core/host_dalvik_static_java_library.mk
@@ -21,7 +21,7 @@
 #
 
 USE_CORE_LIB_BOOTCLASSPATH := true
-LOCAL_JAVA_LIBRARIES += core-hostdex
+LOCAL_JAVA_LIBRARIES += core-libart-hostdex
 
 include $(BUILD_SYSTEM)/host_java_library.mk
 
diff --git a/core/pdk_config.mk b/core/pdk_config.mk
index 6a874fb..fd63820 100644
--- a/core/pdk_config.mk
+++ b/core/pdk_config.mk
@@ -53,7 +53,7 @@
 # all paths under out dir
 PDK_PLATFORM_JAVA_ZIP_JAVA_TARGET_LIB_DIR += \
 	target/common/obj/JAVA_LIBRARIES/android_stubs_current_intermediates \
-	target/common/obj/JAVA_LIBRARIES/core_intermediates \
+	target/common/obj/JAVA_LIBRARIES/core-libart_intermediates \
 	target/common/obj/JAVA_LIBRARIES/core-junit_intermediates \
 	target/common/obj/JAVA_LIBRARIES/ext_intermediates \
 	target/common/obj/JAVA_LIBRARIES/framework_intermediates \
diff --git a/core/tasks/cts.mk b/core/tasks/cts.mk
index 4b008a9..c6d3d45 100644
--- a/core/tasks/cts.mk
+++ b/core/tasks/cts.mk
@@ -101,7 +101,7 @@
 	$(PRIVATE_PARAMS) CollectAllTests $(1) $(2) $(3) "$(4)" $(5) $(6)
 endef
 
-CORE_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,core,,COMMON)
+CORE_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,core-libart,,COMMON)
 CONSCRYPT_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,conscrypt,,COMMON)
 BOUNCYCASTLE_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,bouncycastle,,COMMON)
 APACHEXML_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,apache-xml,,COMMON)
@@ -308,7 +308,7 @@
 CORE_VM_TEST_TF_DESC := $(CTS_TESTCASES_OUT)/android.core.vm-tests-tf.xml
 
 # core tests only needed to get hold of junit-framework-classes
-CORE_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,core,,COMMON)
+CORE_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,core-libart,,COMMON)
 JUNIT_INTERMEDIATES :=$(call intermediates-dir-for,JAVA_LIBRARIES,core-junit,,COMMON)
 
 GEN_CLASSPATH := $(CORE_INTERMEDIATES)/classes.jar:$(JUNIT_INTERMEDIATES)/classes.jar:$(VMTESTSTF_JAR):$(DDMLIB_JAR):$(TF_JAR)
diff --git a/target/product/core_minimal.mk b/target/product/core_minimal.mk
index 8740d80..368e468 100644
--- a/target/product/core_minimal.mk
+++ b/target/product/core_minimal.mk
@@ -76,7 +76,7 @@
 
 # The order of PRODUCT_BOOT_JARS matters.
 PRODUCT_BOOT_JARS := \
-    core \
+    core-libart \
     conscrypt \
     okhttp \
     core-junit \
diff --git a/target/product/core_tiny.mk b/target/product/core_tiny.mk
index 856924c..affef3c 100644
--- a/target/product/core_tiny.mk
+++ b/target/product/core_tiny.mk
@@ -77,7 +77,7 @@
 
 # The order matters
 PRODUCT_BOOT_JARS := \
-    core \
+    core-libart \
     conscrypt \
     okhttp \
     core-junit \
diff --git a/target/product/sdk_arm64.mk b/target/product/sdk_arm64.mk
index 582a779..6b177e8 100644
--- a/target/product/sdk_arm64.mk
+++ b/target/product/sdk_arm64.mk
@@ -20,6 +20,7 @@
 # entirely appropriate to inherit from for on-device configurations.
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk.mk)
+$(call inherit-product, $(SRC_TARGET_DIR)/product/core_64_bit.mk)
 
 # Overrides
 PRODUCT_BRAND := generic_arm64
diff --git a/target/product/sdk_mips64.mk b/target/product/sdk_mips64.mk
index c00de06..d5ab824 100644
--- a/target/product/sdk_mips64.mk
+++ b/target/product/sdk_mips64.mk
@@ -20,6 +20,7 @@
 # entirely appropriate to inherit from for on-device configurations.
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk.mk)
+$(call inherit-product, $(SRC_TARGET_DIR)/product/core_64_bit.mk)
 
 # Overrides
 PRODUCT_BRAND := generic_mips64
diff --git a/target/product/sdk_x86_64.mk b/target/product/sdk_x86_64.mk
index 3816cf9..d50d1c4 100644
--- a/target/product/sdk_x86_64.mk
+++ b/target/product/sdk_x86_64.mk
@@ -20,6 +20,7 @@
 # entirely appropriate to inherit from for on-device configurations.
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk.mk)
+$(call inherit-product, $(SRC_TARGET_DIR)/product/core_64_bit.mk)
 
 # Overrides
 PRODUCT_BRAND := generic_x86_64
diff --git a/tools/droiddoc/templates-sdk/assets/css/default.css b/tools/droiddoc/templates-sdk/assets/css/default.css
index 47cef96..28dced5 100644
--- a/tools/droiddoc/templates-sdk/assets/css/default.css
+++ b/tools/droiddoc/templates-sdk/assets/css/default.css
@@ -2362,6 +2362,13 @@
 #doc-col {
   margin-right:0;
 }
+
+/* Uncomment this for preview release watermark
+#doc-col {
+  background: url('../images/preview.png') repeat;
+}
+*/
+
 #doc-content-container {
   margin-left: 291px
 }
diff --git a/tools/droiddoc/templates-sdk/assets/images/preview.png b/tools/droiddoc/templates-sdk/assets/images/preview.png
new file mode 100644
index 0000000..e5856db
--- /dev/null
+++ b/tools/droiddoc/templates-sdk/assets/images/preview.png
Binary files differ
diff --git a/tools/releasetools/ota_from_target_files b/tools/releasetools/ota_from_target_files
index 85888f8..5f2354c 100755
--- a/tools/releasetools/ota_from_target_files
+++ b/tools/releasetools/ota_from_target_files
@@ -71,6 +71,10 @@
       instead of the binary in the build's target_files.  Use for
       development only.
 
+  -t  (--worker_threads) <int>
+      Specifies the number of worker-threads that will be used when
+      generating patches for incremental updates (defaults to 3).
+
 """
 
 import sys
@@ -1421,8 +1425,12 @@
         OPTIONS.aslr_mode = True
       else:
         OPTIONS.aslr_mode = False
-    elif o in ("--worker_threads"):
-      OPTIONS.worker_threads = int(a)
+    elif o in ("-t", "--worker_threads"):
+      if a.isdigit():
+        OPTIONS.worker_threads = int(a)
+      else:
+        raise ValueError("Cannot parse value %r for option %r - only "
+                         "integers are allowed." % (a, o))
     elif o in ("-2", "--two_step"):
       OPTIONS.two_step = True
     elif o == "--no_signing":
@@ -1436,7 +1444,7 @@
     return True
 
   args = common.ParseOptions(argv, __doc__,
-                             extra_opts="b:k:i:d:wne:a:2o:",
+                             extra_opts="b:k:i:d:wne:t:a:2o:",
                              extra_long_opts=["board_config=",
                                               "package_key=",
                                               "incremental_from=",