diff a/src/java.base/share/classes/java/nio/file/Path.java b/src/java.base/share/classes/java/nio/file/Path.java
--- a/src/java.base/share/classes/java/nio/file/Path.java
+++ b/src/java.base/share/classes/java/nio/file/Path.java
@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
@@ -246,10 +246,54 @@
      * @return  a path representing the name of the file or directory, or
      *          {@code null} if this path has zero elements
      */
     Path getFileName();
 
+    /**
+     * Returns the extension of the file name of this path as a {@code String},
+     * where the extension is defined to be the portion of the {@code String}
+     * representation of the file name after the last dot ('.').  If the first
+     * character in the file name string is a dot it is ignored.  If the
+     * extension cannot be determined, then the empty string is returned.  This
+     * will occur if the path has zero elements ({@link #getFileName()} returns
+     * {@code null}), or the file name string  has fewer than three characters,
+     * does not contain a dot, only the first character is a dot, or the last
+     * character is a dot.
+     *
+     * @implSpec
+     * The default implementation is equivalent for this path to:
+     * <pre>{@code
+     *     String name = getFileName().toString();
+     *     int length = name.length();
+     *     int lastDot = name.lastIndexOf('.');
+     *     length > 2 && lastDot > 0 && lastDot < length - 1 ?
+     *         name.substring(lastDot + 1) : "";
+     * }</pre>
+     *
+     * @return  the extension of the file name of this path, or the empty
+     *          string if the extension is indeterminate
+     */
+    default String getExtension() {
+        Path fileName = getFileName();
+        if (fileName == null) {
+            return "";
+        }
+
+        String fileNameString = fileName.toString();
+        int length = fileNameString.length();
+
+        // Indeterminate if fileNameString is too short
+        if (length > 2) {
+            int lastDotIndex = fileNameString.lastIndexOf('.');
+            // Indeterminate if no dot or found at last or only the first index
+            if (lastDotIndex > 0 && lastDotIndex < length - 1) {
+                return fileNameString.substring(lastDotIndex + 1);
+            }
+        }
+        return "";
+    }
+
     /**
      * Returns the <em>parent path</em>, or {@code null} if this path does not
      * have a parent.
      *
      * <p> The parent of this path object consists of this path's root