The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
As mentioned previously, the java.nio.file
package, and the Path
class in particular, is "link aware." Every Path
method either detects what to do when a symbolic link is encountered, or it provides an option enabling you to configure the behavior when a symbolic link is encountered.
The discussion so far has been about symbolic or soft links, but some file systems also support hard links. Hard links are more restrictive than symbolic links, as follows:
Because of these restrictions, hard links are not used as often as symbolic links, but the Path
methods work seamlessly with hard links.
Several methods deal specifically with links and are covered in the following sections:
If your file system supports it, you can create a symbolic link by using the
createSymbolicLink(Path, Path, FileAttribute<?>)
method. The second Path
argument represents the target file or directory and might or might not exist. The following code snippet creates a symbolic link with default permissions:
Path newLink = ...; Path target = ...; try { Files.createSymbolicLink(newLink, target); } catch (IOException x) { System.err.println(x); } catch (UnsupportedOperationException x) { // Some file systems do not support symbolic links. System.err.println(x); }
The FileAttributes
vararg enables you to specify initial file attributes that are set atomically when the link is created. However, this argument is intended for future use and is not currently implemented.
You can create a hard (or regular) link to an existing file by using the
createLink(Path, Path)
method. The second Path
argument locates the existing file, and it must exist or a NoSuchFileException
is thrown. The following code snippet shows how to create a link:
Path newLink = ...; Path existingFile = ...; try { Files.createLink(newLink, existingFile); } catch (IOException x) { System.err.println(x); } catch (UnsupportedOperationException x) { // Some file systems do not // support adding an existing // file to a directory. System.err.println(x); }
To determine whether a Path
instance is a symbolic link, you can use the
isSymbolicLink(Path)
method. The following code snippet shows how:
Path file = ...; boolean isSymbolicLink = Files.isSymbolicLink(file);
For more information, see Managing Metadata.
You can obtain the target of a symbolic link by using the
readSymbolicLink(Path)
method, as follows:
Path link = ...; try { System.out.format("Target of link" + " '%s' is '%s'%n", link, Files.readSymbolicLink(link)); } catch (IOException x) { System.err.println(x); }
If the Path
is not a symbolic link, this method throws a NotLinkException
.