CLDC 8 (JSR360 Final Release)

Package java.nio.file

Defines interfaces and classes for the Java virtual machine to access files, file attributes, and file systems.

See: Description

Package java.nio.file Description

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 java.nio.file.attribute package.

The following features of NIO are NOT supported by this subset:

Minimal NIO File Implementation

The minimum implementation requires the default FileSystem with zero or more FileStores and zero or more RootDirectories. 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.


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 SYNC and 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 filesystem, and the file resides on a local storage device, and the seekable channel is connected to a file that was opened with one of these options, then an invocation of the 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.

General Exceptions

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

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

Optional Specific Exceptions

Most of the methods defined by classes in this package that access the file system specify that 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 IOException is thrown.
1.7, CLDC1.8
CLDC 8 (JSR360 Final Release)
April 15, 2014

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