diff --git a/make/common/shared/Defs-java.gmk b/make/common/shared/Defs-java.gmk
index 9d918af877dfe6b2c80a932544d01eba86b29abf..f9ed635313135f7d95d0102244c53c1724389337 100644
--- a/make/common/shared/Defs-java.gmk
+++ b/make/common/shared/Defs-java.gmk
@@ -201,7 +201,10 @@ endif
 ifeq ($(JAVAC_WARNINGS_FATAL), true)
   BOOT_JAVACFLAGS  += -Werror
 endif
-BOOT_JAVACFLAGS  += -encoding ascii
+
+BOOT_SOURCE_LANGUAGE_VERSION = 6
+BOOT_TARGET_CLASS_VERSION = 6
+BOOT_JAVACFLAGS  += -encoding ascii -source $(BOOT_SOURCE_LANGUAGE_VERSION) -target $(BOOT_TARGET_CLASS_VERSION)
 BOOT_JAR_JFLAGS += $(JAR_JFLAGS)
 
 BOOT_JAVACFLAGS  += $(NO_PROPRIETARY_API_WARNINGS)