diff --git a/core/combo/javac.mk b/core/combo/javac.mk
index 8c24e4b..528e556 100644
--- a/core/combo/javac.mk
+++ b/core/combo/javac.mk
@@ -9,7 +9,7 @@
 #   COMMON_JAVAC -- Java compiler command with common arguments
 #
 
-ifeq ($(EXPERIMENTAL_USE_JAVA7),)
+ifneq ($(LEGACY_USE_JAVA6),)
 common_flags := -target 1.5 -Xmaxerrs 9999999
 else
 common_flags := -source 1.7 -target 1.7 -Xmaxerrs 9999999
diff --git a/core/config.mk b/core/config.mk
index acbf94a..8290f9a 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -362,7 +362,7 @@
 OLD_FLEX := prebuilts/misc/$(HOST_PREBUILT_TAG)/flex/flex-2.5.4a$(HOST_EXECUTABLE_SUFFIX)
 
 ifeq ($(HOST_OS),darwin)
-ifneq ($(EXPERIMENTAL_USE_JAVA7),)
+ifeq ($(LEGACY_USE_JAVA6),)
 HOST_JDK_TOOLS_JAR:= $(shell $(BUILD_SYSTEM)/find-jdk-tools-jar.sh)
 else
 # Deliberately set to blank for Java 6 installations on MacOS. These
diff --git a/core/main.mk b/core/main.mk
index c4b538d..992f6e1 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -103,7 +103,7 @@
 # Include the google-specific config
 -include vendor/google/build/config.mk
 
-VERSION_CHECK_SEQUENCE_NUMBER := 4
+VERSION_CHECK_SEQUENCE_NUMBER := 5
 -include $(OUT_DIR)/versions_checked.mk
 ifneq ($(VERSION_CHECK_SEQUENCE_NUMBER),$(VERSIONS_CHECKED))
 
@@ -140,19 +140,48 @@
 $(error Directory names containing spaces not supported)
 endif
 
+java_version_str := $(shell unset _JAVA_OPTIONS && java -version 2>&1)
+javac_version_str := $(shell unset _JAVA_OPTIONS && javac -version 2>&1)
+
+# Check for the correct version of java, should be 1.7 by
+# default, and 1.6 if LEGACY_USE_JAVA6 is set.
+ifeq ($(LEGACY_USE_JAVA6),)
+required_version := "1.7.x"
+required_javac_version := "1.7"
+java_version := $(shell echo '$(java_version_str)' | grep '^java .*[ "]1\.7[\. "$$]')
+javac_version := $(shell echo '$(javac_version_str)' | grep '[ "]1\.7[\. "$$]')
+else # if LEGACY_USE_JAVA6
+required_version := "1.6.x"
+required_javac_version := "1.6"
+java_version := $(shell echo '$(java_version_str)' | grep '^java .*[ "]1\.6[\. "$$]')
+javac_version := $(shell echo '$(javac_version_str)' | grep '[ "]1\.6[\. "$$]')
+endif # if LEGACY_USE_JAVA6
+
+ifeq ($(strip $(java_version)),)
+$(info ************************************************************)
+$(info You are attempting to build with the incorrect version)
+$(info of java.)
+$(info $(space))
+$(info Your version is: $(java_version_str).)
+$(info The required version is: $(required_version))
+$(info $(space))
+$(info Please follow the machine setup instructions at)
+$(info $(space)$(space)$(space)$(space)https://source.android.com/source/initializing.html)
+$(info ************************************************************)
+$(error stop)
+endif
+
 # Check for the current JDK.
 #
 # For Java 1.7, we require OpenJDK on linux and Oracle JDK on Mac OS.
 # For Java 1.6, we require Oracle for all host OSes.
 requires_openjdk := false
-ifneq ($(EXPERIMENTAL_USE_JAVA7),)
+ifeq ($(LEGACY_USE_JAVA6),)
 ifeq ($(HOST_OS), linux)
 requires_openjdk := true
 endif
 endif
 
-java_version_str := $(shell unset _JAVA_OPTIONS && java -version 2>&1)
-javac_version_str := $(shell unset _JAVA_OPTIONS && javac -version 2>&1)
 
 # Check for the current jdk
 ifeq ($(requires_openjdk), true)
@@ -178,45 +207,6 @@
 endif # java version is not Sun Oracle JDK
 endif # if requires_openjdk
 
-# Check for the correct version of java, should be 1.7 if
-# EXPERIMENTAL_USE_JAVA7 is set, 1.6 otherwise.
-ifneq ($(EXPERIMENTAL_USE_JAVA7),)
-required_version := "1.7.x"
-required_javac_version := "1.7"
-java_version := $(shell echo '$(java_version_str)' | grep '^java .*[ "]1\.7[\. "$$]')
-javac_version := $(shell echo '$(javac_version_str)' | grep '[ "]1\.7[\. "$$]')
-else # if EXPERIMENTAL_USE_JAVA7
-required_version := "1.6.x"
-required_javac_version := "1.6"
-java_version := $(shell echo '$(java_version_str)' | grep '^java .*[ "]1\.6[\. "$$]')
-javac_version := $(shell echo '$(javac_version_str)' | grep '[ "]1\.6[\. "$$]')
-endif # if EXPERIMENTAL_USE_JAVA7
-
-ifeq ($(required_javac_version), "1.6")
-$(info ************************************************************)
-$(info You are attempting to build with java 1.6.)
-$(info Java6 support for master builds will be dropped shortly,)
-$(info please upgrade to Java7 as soon as possible.)
-$(info $(space))
-$(info Visit go/android-java7-transition for details. )
-$(info $(space))
-$(info ************************************************************)
-endif
-
-ifeq ($(strip $(java_version)),)
-$(info ************************************************************)
-$(info You are attempting to build with the incorrect version)
-$(info of java.)
-$(info $(space))
-$(info Your version is: $(java_version_str).)
-$(info The required version is: $(required_version))
-$(info $(space))
-$(info Please follow the machine setup instructions at)
-$(info $(space)$(space)$(space)$(space)https://source.android.com/source/download.html)
-$(info ************************************************************)
-$(error stop)
-endif
-
 # Check for the correct version of javac
 ifeq ($(strip $(javac_version)),)
 $(info ************************************************************)