diff a/src/java.base/share/classes/java/net/StandardProtocolFamily.java b/src/java.base/share/classes/java/net/StandardProtocolFamily.java
--- a/src/java.base/share/classes/java/net/StandardProtocolFamily.java
+++ b/src/java.base/share/classes/java/net/StandardProtocolFamily.java
@@ -39,7 +39,13 @@
     INET,
 
     /**
      * Internet Protocol Version 6 (IPv6)
      */
-    INET6
+    INET6,
+
+    /**
+     * Unix domain (Local) interprocess communication.
+     * @since 16
+     */
+    UNIX
 }