/* * Copyright (c) 2007, 2011, 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 * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /** * Defines interfaces and classes for the Java virtual machine to access files, * file attributes, and file systems. * *

The java.nio.file package defines classes to access files and file * systems. The API to access file and file system attributes is defined in the * {@link java.nio.file.attribute} package. The {@link java.nio.file.spi} * package is used by service provider implementors wishing to extend the * platform default provider, or to construct other provider implementations.

* *

Symbolic Links

* Many operating systems and file systems support for symbolic links. * A symbolic link is a special file that serves as a reference to another file. * For the most part, symbolic links are transparent to applications and * operations on symbolic links are automatically redirected to the target * of the link. Exceptions to this are when a symbolic link is deleted or * renamed/moved in which case the link is deleted or removed rather than the * target of the link. This package includes support for symbolic links where * implementations provide these semantics. File systems may support other types * that are semantically close but support for these other types of links is * not included in this package.

* *

Interoperability

* The {@link java.io.File} class defines the {@link java.io.File#toPath * toPath} method to construct a {@link java.nio.file.Path} by converting * the abstract path represented by the {@code java.io.File} object. The resulting * {@code Path} can be used to operate on the same file as the {@code File} * object. The {@code Path} specification provides further information * on the interoperability between {@code Path} * and {@code java.io.File} objects.

* *

Visibility

* The view of the files and file system provided by classes in this package are * guaranteed to be consistent with other views provided by other instances in the * same Java virtual machine. The view may or may not, however, be consistent with * the view of the file system as seen by other concurrently running programs due * to caching performed by the underlying operating system and delays induced by * network-filesystem protocols. This is true regardless of the language in which * these other programs are written, and whether they are running on the same machine * or on some other machine. The exact nature of any such inconsistencies are * system-dependent and are therefore unspecified.

* *

Synchronized I/O File Integrity

* The {@link java.nio.file.StandardOpenOption#SYNC SYNC} and {@link * java.nio.file.StandardOpenOption#DSYNC DSYNC} options are used when opening a file * to require that updates to the file are written synchronously to the underlying * storage device. In the case of the default provider, and the file resides on * a local storage device, and the {@link java.nio.channels.SeekableByteChannel * seekable} channel is connected to a file that was opened with one of these * options, then an invocation of the {@link * java.nio.channels.WritableByteChannel#write(java.nio.ByteBuffer) write} * method is only guaranteed to return when all changes made to the file * by that invocation have been written to the device. These options are useful * for ensuring that critical information is not lost in the event of a system * crash. If the file does not reside on a local device then no such guarantee * is made. Whether this guarantee is possible with other {@link * java.nio.file.spi.FileSystemProvider provider} implementations is provider * specific.

* *

General Exceptions

* Unless otherwise noted, passing a {@code null} argument to a constructor * or method of any class or interface in this package will cause a {@link * java.lang.NullPointerException NullPointerException} to be thrown. Additionally, * invoking a method with a collection containing a {@code null} element will * cause a {@code NullPointerException}, unless otherwise specified.

* *

Unless otherwise noted, methods that attempt to access the file system * will throw {@link java.nio.file.ClosedFileSystemException} when invoked on * objects associated with a {@link java.nio.file.FileSystem} that has been * {@link java.nio.file.FileSystem#close closed}. Additionally, any methods * that attempt write access to a file system will throw {@link * java.nio.file.ReadOnlyFileSystemException} when invoked on an object associated * with a {@link java.nio.file.FileSystem} that only provides read-only * access.

* *

Unless otherwise noted, invoking a method of any class or interface in * this package created by one {@link java.nio.file.spi.FileSystemProvider * provider} with a parameter that is an object created by another provider, * will throw {@link java.nio.file.ProviderMismatchException}.

* *

Optional Specific Exceptions

* Most of the methods defined by classes in this package that access the * file system specify that {@link java.io.IOException} be thrown when an I/O * error occurs. In some cases, these methods define specific I/O exceptions * for common cases. These exceptions, noted as optional specific exceptions, * are thrown by the implementation where it can detect the specific error. * Where the specific error cannot be detected then the more general {@code * IOException} is thrown. * * @since 1.7 */ package java.nio.file;