8378115: (fs) sun.nio.fs.NativeBuffer no longer needs a cleaner

Reviewed-by: alanb

src/java.base/share/classes/sun/nio/fs/NativeBuffer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2026, 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
@@ -25,9 +25,7 @@
 
 package sun.nio.fs;
 
-import java.lang.ref.Cleaner.Cleanable;
 import jdk.internal.misc.Unsafe;
-import jdk.internal.ref.CleanerFactory;
 
 /**
  * A light-weight buffer in native memory.
@@ -38,27 +36,17 @@ class NativeBuffer implements AutoCloseable {
 
     private final long address;
     private final int size;
-    private final Cleanable cleanable;
 
     // optional "owner" to avoid copying
     // (only safe for use by thread-local caches)
     private Object owner;
 
-    private static class Deallocator implements Runnable {
-        private final long address;
-        Deallocator(long address) {
-            this.address = address;
-        }
-        public void run() {
-            unsafe.freeMemory(address);
-        }
-    }
+    // owner thread ID
+    private long ownerTid;
 
     NativeBuffer(int size) {
         this.address = unsafe.allocateMemory(size);
         this.size = size;
-        this.cleanable = CleanerFactory.cleaner()
-                                       .register(this, new Deallocator(address));
     }
 
     @Override
@@ -79,16 +67,26 @@ class NativeBuffer implements AutoCloseable {
     }
 
     void free() {
-        cleanable.clean();
+        unsafe.freeMemory(address);
     }
 
     // not synchronized; only safe for use by thread-local caches
     void setOwner(Object owner) {
+        Thread thread = Thread.currentThread();
+        assert !thread.isVirtual();
+        assert ownerTid == 0 || ownerTid == thread.threadId();
         this.owner = owner;
+        this.ownerTid = (owner != null) ? thread.threadId() : 0;
     }
 
     // not synchronized; only safe for use by thread-local caches
     Object owner() {
-        return owner;
+        long tid = Thread.currentThread().threadId();
+        assert ownerTid == 0 || ownerTid == tid;
+        if (ownerTid == tid) {
+            return owner;
+        } else {
+            return null;
+        }
     }
 }

src/java.base/share/classes/sun/nio/fs/NativeBuffers.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2026, 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
@@ -92,7 +92,8 @@ class NativeBuffers {
     static NativeBuffer getNativeBuffer(int size) {
         NativeBuffer buffer = getNativeBufferFromCache(size);
         if (buffer != null) {
-            buffer.setOwner(null);
+            if (!Thread.currentThread().isVirtual())
+                buffer.setOwner(null);
             return buffer;
         } else {
             return allocNativeBuffer(size);

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2026, 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
@@ -47,7 +47,8 @@ class UnixNativeDispatcher {
                 return buffer;
         }
         NativeBuffers.copyCStringToNativeBuffer(cstr, buffer);
-        buffer.setOwner(path);
+        if (!Thread.currentThread().isVirtual())
+            buffer.setOwner(path);
         return buffer;
     }
 

src/java.base/windows/classes/sun/nio/fs/WindowsNativeDispatcher.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2026, 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
@@ -1085,7 +1085,8 @@ class WindowsNativeDispatcher {
         unsafe.copyMemory(chars, Unsafe.ARRAY_CHAR_BASE_OFFSET, null,
             buffer.address(), (long)stringLengthInBytes);
         unsafe.putChar(buffer.address() + stringLengthInBytes, (char)0);
-        buffer.setOwner(s);
+        if (!Thread.currentThread().isVirtual())
+            buffer.setOwner(s);
         return buffer;
     }