# HG changeset patch
# User martin
# Date 1543256640 28800
#      Mon Nov 26 10:24:00 2018 -0800
# Node ID 4a725dd89094d3b1227c1247388782a955285c61
# Parent  e017d2f176d0119cdc70c9f2ee98e78c0c13f0c7
8213406: (fs) More than one instance of built-in FileSystem observed in heap
Reviewed-by: alanb, cushon, weijun

diff --git a/src/java.base/aix/classes/sun/nio/fs/AixFileSystemProvider.java b/src/java.base/aix/classes/sun/nio/fs/AixFileSystemProvider.java
--- a/src/java.base/aix/classes/sun/nio/fs/AixFileSystemProvider.java
+++ b/src/java.base/aix/classes/sun/nio/fs/AixFileSystemProvider.java
@@ -32,7 +32,7 @@
  * AIX implementation of FileSystemProvider
  */
 
-public class AixFileSystemProvider extends UnixFileSystemProvider {
+class AixFileSystemProvider extends UnixFileSystemProvider {
     public AixFileSystemProvider() {
         super();
     }
diff --git a/src/java.base/aix/classes/sun/nio/fs/DefaultFileSystemProvider.java b/src/java.base/aix/classes/sun/nio/fs/DefaultFileSystemProvider.java
--- a/src/java.base/aix/classes/sun/nio/fs/DefaultFileSystemProvider.java
+++ b/src/java.base/aix/classes/sun/nio/fs/DefaultFileSystemProvider.java
@@ -25,19 +25,21 @@
 
 package sun.nio.fs;
 
-import java.nio.file.spi.FileSystemProvider;
+import java.nio.file.FileSystem;
 
 /**
- * Creates this platform's default FileSystemProvider.
+ * Creates this platform's system-default ("builtin") FileSystemProvider.
  */
 
 public class DefaultFileSystemProvider {
     private DefaultFileSystemProvider() { }
 
-    /**
-     * Returns the default FileSystemProvider.
-     */
-    public static FileSystemProvider create() {
-        return new AixFileSystemProvider();
+    /** The unique instance of the system-default file system provider. */
+    public static final AixFileSystemProvider FILE_SYSTEM_PROVIDER
+        = new AixFileSystemProvider();
+
+    /** Returns the unique instance of the system-default file system. */
+    public static FileSystem theFileSystem() {
+        return FILE_SYSTEM_PROVIDER.theFileSystem;
     }
 }
diff --git a/src/java.base/linux/classes/sun/nio/fs/DefaultFileSystemProvider.java b/src/java.base/linux/classes/sun/nio/fs/DefaultFileSystemProvider.java
--- a/src/java.base/linux/classes/sun/nio/fs/DefaultFileSystemProvider.java
+++ b/src/java.base/linux/classes/sun/nio/fs/DefaultFileSystemProvider.java
@@ -25,19 +25,21 @@
 
 package sun.nio.fs;
 
-import java.nio.file.spi.FileSystemProvider;
+import java.nio.file.FileSystem;
 
 /**
- * Creates this platform's default FileSystemProvider.
+ * Creates this platform's system-default ("builtin") FileSystemProvider.
  */
 
 public class DefaultFileSystemProvider {
     private DefaultFileSystemProvider() { }
 
-    /**
-     * Returns the default FileSystemProvider.
-     */
-    public static FileSystemProvider create() {
-        return new LinuxFileSystemProvider();
+    /** The unique instance of the system-default file system provider. */
+    public static final LinuxFileSystemProvider FILE_SYSTEM_PROVIDER
+        = new LinuxFileSystemProvider();
+
+    /** Returns the unique instance of the system-default file system. */
+    public static FileSystem theFileSystem() {
+        return FILE_SYSTEM_PROVIDER.theFileSystem;
     }
 }
diff --git a/src/java.base/linux/classes/sun/nio/fs/LinuxFileSystemProvider.java b/src/java.base/linux/classes/sun/nio/fs/LinuxFileSystemProvider.java
--- a/src/java.base/linux/classes/sun/nio/fs/LinuxFileSystemProvider.java
+++ b/src/java.base/linux/classes/sun/nio/fs/LinuxFileSystemProvider.java
@@ -36,7 +36,7 @@
  * Linux implementation of FileSystemProvider
  */
 
-public class LinuxFileSystemProvider extends UnixFileSystemProvider {
+class LinuxFileSystemProvider extends UnixFileSystemProvider {
     public LinuxFileSystemProvider() {
         super();
     }
diff --git a/src/java.base/macosx/classes/sun/nio/fs/BsdFileSystemProvider.java b/src/java.base/macosx/classes/sun/nio/fs/BsdFileSystemProvider.java
--- a/src/java.base/macosx/classes/sun/nio/fs/BsdFileSystemProvider.java
+++ b/src/java.base/macosx/classes/sun/nio/fs/BsdFileSystemProvider.java
@@ -31,7 +31,7 @@
  * Bsd implementation of FileSystemProvider
  */
 
-public class BsdFileSystemProvider extends UnixFileSystemProvider {
+class BsdFileSystemProvider extends UnixFileSystemProvider {
     public BsdFileSystemProvider() {
         super();
     }
diff --git a/src/java.base/macosx/classes/sun/nio/fs/DefaultFileSystemProvider.java b/src/java.base/macosx/classes/sun/nio/fs/DefaultFileSystemProvider.java
--- a/src/java.base/macosx/classes/sun/nio/fs/DefaultFileSystemProvider.java
+++ b/src/java.base/macosx/classes/sun/nio/fs/DefaultFileSystemProvider.java
@@ -25,19 +25,21 @@
 
 package sun.nio.fs;
 
-import java.nio.file.spi.FileSystemProvider;
+import javaimport java.nio.file.FileSystem;
 
 /**
- * Creates this platform's default FileSystemProvider.
+ * Creates this platform's system-default ("builtin") FileSystemProvider.
  */
 
 public class DefaultFileSystemProvider {
     private DefaultFileSystemProvider() { }
 
-    /**
-     * Returns the default FileSystemProvider.
-     */
-    public static FileSystemProvider create() {
-        return new MacOSXFileSystemProvider();
+    /** The unique instance of the system-default file system provider. */
+    public static final MacOSXFileSystemProvider FILE_SYSTEM_PROVIDER
+        = new MacOSXFileSystemProvider();
+
+    /** Returns the unique instance of the system-default file system. */
+    public static FileSystem theFileSystem() {
+        return FILE_SYSTEM_PROVIDER.theFileSystem;
     }
 }
diff --git a/src/java.base/macosx/classes/sun/nio/fs/MacOSXFileSystemProvider.java b/src/java.base/macosx/classes/sun/nio/fs/MacOSXFileSystemProvider.java
--- a/src/java.base/macosx/classes/sun/nio/fs/MacOSXFileSystemProvider.java
+++ b/src/java.base/macosx/classes/sun/nio/fs/MacOSXFileSystemProvider.java
@@ -34,7 +34,7 @@
  * MacOSX implementation of FileSystemProvider
  */
 
-public class MacOSXFileSystemProvider extends BsdFileSystemProvider {
+class MacOSXFileSystemProvider extends BsdFileSystemProvider {
     public MacOSXFileSystemProvider() {
         super();
     }
diff --git a/src/java.base/share/classes/java/io/FilePermission.java b/src/java.base/share/classes/java/io/FilePermission.java
--- a/src/java.base/share/classes/java/io/FilePermission.java
+++ b/src/java.base/share/classes/java/io/FilePermission.java
@@ -25,7 +25,6 @@
 
 package java.io;
 
-import java.net.URI;
 import java.nio.file.*;
 import java.security.*;
 import java.util.Enumeration;
@@ -198,13 +197,12 @@
 
     private static final long serialVersionUID = 7930732926638008763L;
 
-    /**
-     * Always use the internal default file system, in case it was modified
-     * with java.nio.file.spi.DefaultFileSystemProvider.
+     /**
+     * Always use the builtin system-default file system, in case the
+     * java.nio.file.spi.DefaultFileSystemProvider system property is set.
      */
     private static final java.nio.file.FileSystem builtInFS =
-            DefaultFileSystemProvider.create()
-                    .getFileSystem(URI.create("file:///"));
+        DefaultFileSystemProvider.theFileSystem();
 
     private static final Path here = builtInFS.getPath(
             GetPropertyAction.privilegedGetProperty("user.dir"));
@@ -326,7 +324,7 @@
 
             if (name.equals("<<ALL FILES>>")) {
                 allFiles = true;
-                npath = builtInFS.getPath("");
+                npath = EMPTY_PATH;
                 // other fields remain default
                 return;
             }
@@ -351,7 +349,7 @@
                     npath = npath.getParent();
                 }
                 if (npath == null) {
-                    npath = builtInFS.getPath("");
+                    npath = EMPTY_PATH;
                 }
                 invalid = false;
             } catch (InvalidPathException ipe) {
diff --git a/src/java.base/share/classes/java/nio/file/FileSystems.java b/src/java.base/share/classes/java/nio/file/FileSystems.java
--- a/src/java.base/share/classes/java/nio/file/FileSystems.java
+++ b/src/java.base/share/classes/java/nio/file/FileSystems.java
@@ -88,16 +88,6 @@
 public final class FileSystems {
     private FileSystems() { }
 
-    // Built-in file system provider
-    private static final FileSystemProvider builtinFileSystemProvider =
-        sun.nio.fs.DefaultFileSystemProvider.create();
-
-    // built-in file system
-    private static class BuiltinFileSystemHolder {
-        static final FileSystem builtinFileSystem =
-            builtinFileSystemProvider.getFileSystem(URI.create("file:///"));
-    }
-
     // lazy initialization of default file system
     private static class DefaultFileSystemHolder {
         static final FileSystem defaultFileSystem = defaultFileSystem();
@@ -118,7 +108,8 @@
 
         // returns default provider
         private static FileSystemProvider getDefaultProvider() {
-            FileSystemProvider provider = builtinFileSystemProvider;
+            FileSystemProvider provider =
+                sun.nio.fs.DefaultFileSystemProvider.FILE_SYSTEM_PROVIDER;
 
             // if the property java.nio.file.spi.DefaultFileSystemProvider is
             // set then its value is the name of the default provider (or a list)
@@ -189,7 +180,7 @@
         if (VM.isModuleSystemInited()) {
             return DefaultFileSystemHolder.defaultFileSystem;
         } else {
-            return BuiltinFileSystemHolder.builtinFileSystem;
+            return sun.nio.fs.DefaultFileSystemProvider.theFileSystem();
         }
     }
 
diff --git a/src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java b/src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java
--- a/src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java
+++ b/src/java.base/share/classes/java/nio/file/spi/FileSystemProvider.java
@@ -101,7 +101,7 @@
  * obtain a reference to an existing file system created by the provider. Where
  * a provider is the factory for a single file system then it is provider dependent
  * if the file system is created when the provider is initialized, or later when
- * the {@code newFileSystem} method is invoked. In the case of the default
+ * the {@code newFileSystem} method is invoked. In the case of the system-default
  * provider, the {@code FileSystem} is created when the provider is initialized.
  *
  * <p> All of the methods in this class are safe for use by multiple concurrent
diff --git a/src/java.base/solaris/classes/sun/nio/fs/DefaultFileSystemProvider.java b/src/java.base/solaris/classes/sun/nio/fs/DefaultFileSystemProvider.java
--- a/src/java.base/solaris/classes/sun/nio/fs/DefaultFileSystemProvider.java
+++ b/src/java.base/solaris/classes/sun/nio/fs/DefaultFileSystemProvider.java
@@ -25,19 +25,21 @@
 
 package sun.nio.fs;
 
-import java.nio.file.spi.FileSystemProvider;
+import java.nio.file.FileSystem;
 
 /**
- * Creates this platform's default FileSystemProvider.
+ * Creates this platform's system-default ("builtin") FileSystemProvider.
  */
 
 public class DefaultFileSystemProvider {
     private DefaultFileSystemProvider() { }
 
-    /**
-     * Returns the default FileSystemProvider.
-     */
-    public static FileSystemProvider create() {
-        return new SolarisFileSystemProvider();
+    /** The unique instance of the system-default file system provider. */
+    public static final SolarisFileSystemProvider FILE_SYSTEM_PROVIDER
+        = new SolarisFileSystemProvider();
+
+    /** Returns the unique instance of the system-default file system. */
+    public static FileSystem theFileSystem() {
+        return FILE_SYSTEM_PROVIDER.theFileSystem;
     }
 }
diff --git a/src/java.base/solaris/classes/sun/nio/fs/SolarisFileSystemProvider.java b/src/java.base/solaris/classes/sun/nio/fs/SolarisFileSystemProvider.java
--- a/src/java.base/solaris/classes/sun/nio/fs/SolarisFileSystemProvider.java
+++ b/src/java.base/solaris/classes/sun/nio/fs/SolarisFileSystemProvider.java
@@ -36,7 +36,7 @@
  * Solaris implementation of FileSystemProvider
  */
 
-public class SolarisFileSystemProvider extends UnixFileSystemProvider {
+class SolarisFileSystemProvider extends UnixFileSystemProvider {
     public SolarisFileSystemProvider() {
         super();
     }
diff --git a/src/java.base/unix/classes/sun/nio/fs/UnixFileSystemProvider.java b/src/java.base/unix/classes/sun/nio/fs/UnixFileSystemProvider.java
--- a/src/java.base/unix/classes/sun/nio/fs/UnixFileSystemProvider.java
+++ b/src/java.base/unix/classes/sun/nio/fs/UnixFileSystemProvider.java
@@ -49,7 +49,7 @@
     extends AbstractFileSystemProvider
 {
     private static final String USER_DIR = "user.dir";
-    private final UnixFileSystem theFileSystem;
+    final UnixFileSystem theFileSystem;
 
     public UnixFileSystemProvider() {
         String userDir = System.getProperty(USER_DIR);
diff --git a/src/java.base/windows/classes/sun/nio/fs/DefaultFileSystemProvider.java b/src/java.base/windows/classes/sun/nio/fs/DefaultFileSystemProvider.java
--- a/src/java.base/windows/classes/sun/nio/fs/DefaultFileSystemProvider.java
+++ b/src/java.base/windows/classes/sun/nio/fs/DefaultFileSystemProvider.java
@@ -25,14 +25,20 @@
 
 package sun.nio.fs;
 
-import java.nio.file.spi.FileSystemProvider;
+import java.nio.file.FileSystem;
 
 /**
- * Creates default provider on Windows
+ * Creates this platform's system-default ("builtin") FileSystemProvider.
  */
 public class DefaultFileSystemProvider {
     private DefaultFileSystemProvider() { }
-    public static FileSystemProvider create() {
-        return new WindowsFileSystemProvider();
+
+    /** The unique instance of the system-default file system provider. */
+    public static final WindowsFileSystemProvider FILE_SYSTEM_PROVIDER
+        = new WindowsFileSystemProvider();
+
+    /** Returns the unique instance of the system-default file system. */
+    public static FileSystem theFileSystem() {
+        return FILE_SYSTEM_PROVIDER.theFileSystem;
     }
 }
diff --git a/src/java.base/windows/classes/sun/nio/fs/WindowsFileSystemProvider.java b/src/java.base/windows/classes/sun/nio/fs/WindowsFileSystemProvider.java
--- a/src/java.base/windows/classes/sun/nio/fs/WindowsFileSystemProvider.java
+++ b/src/java.base/windows/classes/sun/nio/fs/WindowsFileSystemProvider.java
@@ -42,12 +42,12 @@
 import static sun.nio.fs.WindowsSecurity.*;
 import static sun.nio.fs.WindowsConstants.*;
 
-public class WindowsFileSystemProvider
+class WindowsFileSystemProvider
     extends AbstractFileSystemProvider
 {
     private static final Unsafe unsafe = Unsafe.getUnsafe();
 
-    private final WindowsFileSystem theFileSystem;
+    final WindowsFileSystem theFileSystem;
 
     public WindowsFileSystemProvider() {
         theFileSystem = new WindowsFileSystem(this, StaticProperty.userDir());