8304591: (fs) UnixPath.stringValue need not be volatile

Reviewed-by: alanb, bpb, shade

src/java.base/unix/classes/sun/nio/fs/UnixPath.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2023, 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
@@ -57,8 +57,8 @@ class UnixPath implements Path {
     // internal representation
     private final byte[] path;
 
-    // String representation (created lazily)
-    private volatile String stringValue;
+    // String representation (created lazily, no need to be volatile)
+    private String stringValue;
 
     // cached hashcode (created lazily, no need to be volatile)
     private int hash;
@@ -761,8 +761,9 @@ public int hashCode() {
     @Override
     public String toString() {
         // OK if two or more threads create a String
+        String stringValue = this.stringValue;
         if (stringValue == null) {
-            stringValue = fs.normalizeJavaPath(Util.toString(path));     // platform encoding
+            this.stringValue = stringValue = fs.normalizeJavaPath(Util.toString(path));     // platform encoding
         }
         return stringValue;
     }