diff --git a/core/config.mk b/core/config.mk
index 7007c5d..2ce064f 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -804,6 +804,9 @@
 # We don't have prebuilt test_current SDK yet.
 TARGET_AVAILABLE_SDK_VERSIONS := test_current $(TARGET_AVAILABLE_SDK_VERSIONS)
 
+TARGET_SDK_VERSIONS_WITHOUT_JAVA_18_SUPPORT := $(call numbers_less_than,24,$(TARGET_AVAILABLE_SDK_VERSIONS))
+TARGET_SDK_VERSIONS_WITHOUT_JAVA_19_SUPPORT := $(call numbers_less_than,27,$(TARGET_AVAILABLE_SDK_VERSIONS))
+
 INTERNAL_PLATFORM_API_FILE := $(TARGET_OUT_COMMON_INTERMEDIATES)/PACKAGING/public_api.txt
 INTERNAL_PLATFORM_REMOVED_API_FILE := $(TARGET_OUT_COMMON_INTERMEDIATES)/PACKAGING/removed.txt
 INTERNAL_PLATFORM_SYSTEM_API_FILE := $(TARGET_OUT_COMMON_INTERMEDIATES)/PACKAGING/system-api.txt
diff --git a/core/definitions.mk b/core/definitions.mk
index 1f9891e..0e7093e 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2251,9 +2251,11 @@
 $(hide) if [ -s $(PRIVATE_JAVA_SOURCE_LIST) ] ; then \
     $(SOONG_JAVAC_WRAPPER) $(1) -encoding UTF-8 \
     $(if $(findstring true,$(PRIVATE_WARNINGS_ENABLE)),$(xlint_unchecked),) \
-    $(addprefix -bootclasspath ,$(strip \
-        $(call normalize-path-list,$(PRIVATE_BOOTCLASSPATH)) \
-        $(PRIVATE_EMPTY_BOOTCLASSPATH))) \
+    $(if $(PRIVATE_USE_SYSTEM_MODULES), \
+      $(addprefix --system=,$(PRIVATE_SYSTEM_MODULES)), \
+      $(addprefix -bootclasspath ,$(strip \
+          $(call normalize-path-list,$(PRIVATE_BOOTCLASSPATH)) \
+          $(PRIVATE_EMPTY_BOOTCLASSPATH)))) \
     $(addprefix -classpath ,$(strip \
         $(call normalize-path-list,$(2)))) \
     $(if $(findstring true,$(PRIVATE_WARNINGS_ENABLE)),$(xlint_unchecked),) \
@@ -2300,6 +2302,7 @@
     $(3) \
     $(5) \
     $$(full_java_bootclasspath_libs) \
+    $$(full_java_system_modules_deps) \
     $$(layers_file) \
     $$(annotation_processor_deps) \
     $$(NORMALIZE_PATH) \
diff --git a/core/host_dalvik_java_library.mk b/core/host_dalvik_java_library.mk
index 96796df..4bfe288 100644
--- a/core/host_dalvik_java_library.mk
+++ b/core/host_dalvik_java_library.mk
@@ -93,6 +93,7 @@
     $(java_sources_deps) \
     $(full_java_header_libs) \
     $(full_java_bootclasspath_libs) \
+    $(full_java_system_modules_deps) \
     $(annotation_processor_deps) \
     $(NORMALIZE_PATH) \
     $(JAR_ARGS) \
diff --git a/core/java.mk b/core/java.mk
index cf49994..7584479 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -499,6 +499,7 @@
     $(java_sources_deps) \
     $(full_java_header_libs) \
     $(full_java_bootclasspath_libs) \
+    $(full_java_system_modules_deps) \
     $(NORMALIZE_PATH) \
     $(JAR_ARGS) \
     $(ZIPTIME) \
diff --git a/core/java_common.mk b/core/java_common.mk
index 320c52f..a73c6db 100644
--- a/core/java_common.mk
+++ b/core/java_common.mk
@@ -15,20 +15,17 @@
 # Modules can override this logic by specifying
 # LOCAL_JAVA_LANGUAGE_VERSION explicitly.
 ifeq (,$(LOCAL_JAVA_LANGUAGE_VERSION))
-  private_sdk_versions_without_any_java_18_support := 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
-  ifneq (,$(filter $(LOCAL_SDK_VERSION), $(private_sdk_versions_without_any_java_18_support)))
+  ifneq (,$(filter $(LOCAL_SDK_VERSION), $(TARGET_SDK_VERSIONS_WITHOUT_JAVA_18_SUPPORT)))
     LOCAL_JAVA_LANGUAGE_VERSION := 1.7
+  else ifneq (,$(filter $(LOCAL_SDK_VERSION), $(TARGET_SDK_VERSIONS_WITHOUT_JAVA_19_SUPPORT)))
+    LOCAL_JAVA_LANGUAGE_VERSION := 1.8
+  else ifneq (,$(LOCAL_SDK_VERSION)$(TARGET_BUILD_APPS))
+    # TODO(ccross): allow 1.9 for current and unbundled once we have SDK system modules
+    LOCAL_JAVA_LANGUAGE_VERSION := 1.8
   else
-    ifneq ($(EXPERIMENTAL_USE_OPENJDK9),true)
-      LOCAL_JAVA_LANGUAGE_VERSION := 1.8
-    else
-      private_sdk_versions_without_any_java_19_support := 24 25 26
-      ifneq (,$(filter $(LOCAL_SDK_VERSION), $(private_sdk_versions_without_any_java_19_support)))
-        LOCAL_JAVA_LANGUAGE_VERSION := 1.8
-      else
-        LOCAL_JAVA_LANGUAGE_VERSION := 1.9
-      endif
-    endif
+    # DEFAULT_JAVA_LANGUAGE_VERSION is 1.8 unless EXPERIMENTAL_USE_OPENJDK9=true
+    # in which case it is 1.9
+    LOCAL_JAVA_LANGUAGE_VERSION := $(DEFAULT_JAVA_LANGUAGE_VERSION)
   endif
 endif
 LOCAL_JAVACFLAGS += -source $(LOCAL_JAVA_LANGUAGE_VERSION) -target $(LOCAL_JAVA_LANGUAGE_VERSION)
@@ -201,6 +198,7 @@
 
 full_java_bootclasspath_libs :=
 empty_bootclasspath :=
+my_system_modules :=
 
 # full_java_libs: The list of files that should be used as the classpath.
 #                 Using this list as a dependency list WILL NOT WORK.
@@ -209,8 +207,13 @@
     ifeq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
       # No bootclasspath. But we still need "" to prevent javac from using default host bootclasspath.
       empty_bootclasspath := ""
+      # Most users of LOCAL_NO_STANDARD_LIBRARIES really mean no framework libs,
+      # and manually add back the core libs.  The ones that don't are in soong
+      # now, so just always assume that they want the default system modules
+      my_system_modules := $(DEFAULT_SYSTEM_MODULES)
     else  # LOCAL_NO_STANDARD_LIBRARIES
       full_java_bootclasspath_libs := $(call java-lib-header-files,$(TARGET_DEFAULT_BOOTCLASSPATH_LIBRARIES))
+      my_system_modules := $(DEFAULT_SYSTEM_MODULES)
     endif  # LOCAL_NO_STANDARD_LIBRARIES
   else
     ifeq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
@@ -255,6 +258,7 @@
       full_java_bootclasspath_libs := $(call java-lib-header-files,$(addsuffix -hostdex,$(TARGET_DEFAULT_BOOTCLASSPATH_LIBRARIES)),true)
     endif
 
+    my_system_modules := $(DEFAULT_SYSTEM_MODULES)
     full_shared_java_libs := $(call java-lib-files,$(LOCAL_JAVA_LIBRARIES),true)
     full_shared_java_header_libs := $(call java-lib-header-files,$(LOCAL_JAVA_LIBRARIES),true)
   else # !USE_CORE_LIB_BOOTCLASSPATH
@@ -270,8 +274,25 @@
   endif
 endif
 
+full_java_system_modules_deps :=
+my_system_modules_dir :=
+$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_USE_SYSTEM_MODULES :=
+ifeq ($(LOCAL_JAVA_LANGUAGE_VERSION),1.9)
+  $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_USE_SYSTEM_MODULES := true
+  ifdef my_system_modules
+    ifneq ($(my_system_modules),none)
+      ifndef SOONG_SYSTEM_MODULES_$(my_system_modules)
+        $(call pretty-error, Invalid system modules $(my_system_modules))
+      endif
+      full_java_system_modules_deps := $(SOONG_SYSTEM_MODULES_$(my_system_modules))
+      my_system_modules_dir := $(patsubst %/lib/modules,%,$(SOONG_SYSTEM_MODULES_$(my_system_modules)))
+    endif
+  endif
+endif
+
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH := $(full_java_bootclasspath_libs)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_EMPTY_BOOTCLASSPATH := $(empty_bootclasspath)
+$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_SYSTEM_MODULES := $(my_system_modules_dir)
 
 full_java_libs := $(full_shared_java_libs) $(full_static_java_libs) $(LOCAL_CLASSPATH)
 full_java_header_libs := $(full_shared_java_header_libs) $(full_static_java_header_libs)
diff --git a/core/math.mk b/core/math.mk
index 57cb681..44e03ce 100644
--- a/core/math.mk
+++ b/core/math.mk
@@ -72,6 +72,10 @@
 $(if $(filter $(1),$(call math_max,$(1),$(2))),true)
 endef
 
+define math_lt
+$(if $(call math_gt_or_eq,$(1),$(2)),,true)
+endef
+
 #$(warning $(call math_gt_or_eq, 2, 1))
 #$(warning $(call math_gt_or_eq, 1, 1))
 #$(warning $(if $(call math_gt_or_eq, 1, 2),false,true))
@@ -81,6 +85,15 @@
 $(strip $(eval $(1) := $($(1)) .)$(words $($(1))))
 endef
 
+# Returns the words in $2 that are numbers and are less than $1
+define numbers_less_than
+$(strip \
+  $(foreach n,$2, \
+    $(if $(call math_is_number,$(n)), \
+      $(if $(call math_lt,$(n),$(1)), \
+        $(n)))))
+endef
+
 _INT_LIMIT_WORDS := $(foreach a,x x,$(foreach b,x x x x x x x x x x x x x x x x,\
   $(foreach c,x x x x x x x x x x x x x x x x,x x x x x x x x x x x x x x x x)))