--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/resources/compiler.properties	Thu Sep 05 12:39:48 2019 +0200
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/resources/compiler.properties	Thu Sep 12 17:47:24 2019 +0200
@@ -1775,6 +1775,14 @@
     {0} in {1} has been deprecated and marked for removal
 
 # 0: symbol
+compiler.warn.is.preview=\
+    {0} is an API that is part of a preview feature
+
+# 0: symbol
+compiler.err.is.preview=\
+    {0} is an API that is part of a preview feature
+
+# 0: symbol
 compiler.warn.has.been.deprecated.module=\
     module {0} has been deprecated