diff --git a/core/main.mk b/core/main.mk
index 14594e7..549c825 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -57,6 +57,9 @@
 
 BUILD_SYSTEM := $(TOPDIR)build/core
 
+# Ensure JAVA_NOT_REQUIRED is not set externally.
+JAVA_NOT_REQUIRED := false
+
 # This is the default target.  It must be the first declared target.
 .PHONY: droid
 DEFAULT_GOAL := droid
@@ -177,6 +180,7 @@
 $(error Directory names containing spaces not supported)
 endif
 
+ifeq ($(JAVA_NOT_REQUIRED), false)
 java_version_str := $(shell unset _JAVA_OPTIONS && java -version 2>&1)
 javac_version_str := $(shell unset _JAVA_OPTIONS && javac -version 2>&1)
 
@@ -256,6 +260,7 @@
 $(error stop)
 endif
 
+endif # if JAVA_NOT_REQUIRED
 
 ifndef BUILD_EMULATOR
   # Emulator binaries are now provided under prebuilts/android-emulator/
diff --git a/tools/signapk/Android.mk b/tools/signapk/Android.mk
index c2cf572..ac217c7 100644
--- a/tools/signapk/Android.mk
+++ b/tools/signapk/Android.mk
@@ -26,6 +26,7 @@
 include $(BUILD_HOST_JAVA_LIBRARY)
 
 ifeq ($(TARGET_BUILD_APPS),)
+ifeq ($(BRILLO),)
 # The post-build signing tools need signapk.jar and its shared libraries,
 # but we don't need this if we're just doing unbundled apps.
 my_dist_files := $(LOCAL_INSTALLED_MODULE) \
@@ -34,3 +35,4 @@
 $(call dist-for-goals,droidcore,$(my_dist_files))
 my_dist_files :=
 endif
+endif