Within Java, both Path and File are distinct classes located in separate packages, yet they serve similar functionalities. The Path class can be considered as an enhanced iteration of the File class, utilized for File Input/Output operations. Let's delve into the variances between the Path and File classes.
Java File Class
Within Java, the File class is part of the java.io package and serves as an abstract model of file and directory paths. While it is commonly utilized for file input/output operations, it does come with several limitations.
Java Path Class
The Java Path class is essentially a replacement for the File class in Java, offering similar functionality. It is part of the java.nio.file package within the updated java.nio.file library. Java Path class facilitates various operations similar to those achievable using the File class, making it a preferred choice for creating new projects.
Path Vs File
Before the introduction of Java SE 1.7, the java.io.File class was commonly employed for file input/output operations. However, this class had various limitations. Some of its methods did not properly handle exceptions, making it challenging to receive informative error messages when operations failed to execute as expected.
In a scenario where a file needs to be removed and a software designed to carry out this task encounters an issue and is unable to execute the deletion, it will display an error message indicating that the deletion has failed. However, the program is not able to pinpoint the specific cause of the failure. Potential reasons for the failure to delete the file could include the file not being present, an incorrect file path being specified, insufficient user permissions, or other underlying factors.
Another limitation is that the Java File class does not provide functionality for symbolic links, also referred to as symlink or soft link. Moreover, the rename method does not exhibit consistent behavior across different platforms. When working with File I/O operations, there is a need for enhanced support for metadata, which is lacking in the File class. This metadata encompasses permissions, file owner information, and security attributes.
The functionalities of the file class were not suitable for handling large-scale operations. Requesting a listing of a sizable directory could potentially overload the server, resulting in a hang. This could further trigger memory resource issues that might result in a Denial of Service (DoS) situation.
Hence, the Java File class is associated with numerous limitations, making it unsuitable for utilization in new project development.
Oracle suggests utilizing the Path class when dealing with legacy code that relies on the java.io.File class. By incorporating the Path class, one can benefit from its features while making only slight modifications to the existing code.
The Java File class offers the toPath function, which is used to transform a traditional file into an instance of java.nio.file.Path. For instance:
Path input = file.toPath();
It offers sophisticated and extensive functionalities found in the Java Path class. Let's say we wish to remove a file:
file.delete();
We have the option to adjust the previous statement by employing the delete function of the Files class in the following manner:
Path fp = file.toPath();
Files.delete(fp);
Upon comparison, it has been observed that the java.nio.file.Path class outperforms the java.io.File class.
Although the Java Path class is preferred, the java.io.File class remains available in newer versions without being deprecated. The Android framework continues to utilize the File class for fundamental file operations.
Mapping java.io.File Functionality to java.nio.file.Path
The file I/O architecture underwent a significant redesign in the Java SE 1.7 version. It is important to note that methods are not interchangeable within this new architecture. When starting a new project that involves file I/O operations and necessitates leveraging the advanced features offered by the java.nio.file package, it is recommended to utilize the toPath method from the File class. While utilizing the functionalities of the Path class is permissible, if these features are inadequate for your requirements, then it is advisable to refactor the file I/O code accordingly.
The table below provides a summary of how the features in the java.io.File API correspond to those in the java.nio.file API.
| java.io.File Functionality | java.nio.file Functionality | Uses |
|---|---|---|
| java.io.File | java.nio.file.Path | It is used to specify the packages. |
| java.io.RandomAccessFile | The SeekableByteChannel functionality. | It is used if we want to randomly access a file. |
| File.canRead, canWrite, canExecute | Files.isReadable, Files.isWritable, and Files.isExecutable.On UNIX file systems, the Managing Metadata (File and File Store Attributes) package is used to check the nine file permissions. | It is used to check the permission granted to the file. |
| File.isDirectory(), File.isFile(), and File.length() | Files.isDirectory(Path, LinkOption...), Files.isRegularFile(Path, LinkOption...), and Files.size(Path) | It is used to retrieve the file's metadata. |
| File.lastModified() and File.setLastModified(long) | Files.getLastModifiedTime(Path, LinkOption...) and Files.setLastMOdifiedTime(Path, FileTime) | |
| The File methods that set various attributes: setExecutable, setReadable, setReadOnly, setWritable | These methods are replaced by the Files method setAttribute(Path, String, Object, LinkOption...). | |
| new File(parent, "newfile") | parent.resolve("newfile") | It performs the Path operations. |
| File.renameTo | Files.move | It is used to move a file to the directory. |
| File.delete | Files.delete | It is used to delete a file or directory. |
| File.createNewFile | Files.createFile | It is used to create new files. |
| File.deleteOnExit | Replaced by the DELETEONCLOSE option specified in the createFile method. | |
| File.createTempFile | Files.createTempFile(Path, String, FileAttributes<?>), Files.createTempFile(Path, String, String, FileAttributes<?>) | It creates a new file and also writes to the file by using the Stream I/O. Also performs reading and writing operations by using the Channel I/O. |
| File.exists | Files.exists and Files.notExists | It checks or verifies if the file exists or not. |
| File.compareTo and equals | Path.compareTo and equals | It is used to compare two paths. |
| File.getAbsolutePath and getAbsoluteFile | Path.toAbsolutePath | It converts the path |
| File.getCanonicalPath and getCanonicalFile | Path.toRealPath or normalize | It is used to normalize (remove redundancies) the path and also convert the path into a real path. |
| File.toURI | Path.toURI | It converts the path to the URI. |
| File.isHidden | Files.isHidden | It is used to retrieve information about the file. |
| File.list and listFiles | Path.newDirectoryStream | It is used to enlist the content of a directory. |
| File.mkdir and mkdirs | Files.createDirectory | It is used to create a directory. |
| File.listRoots | FileSystem.getRootDirectories | It is used to enlist the files of the system's root directory. |
| File.getTotalSpace, File.getFreeSpace, File.getUsableSpace | FileStore.getTotalSpace, FileStore.getUnallocatedSpace, FileStore.getUsableSpace, FileStore.getTotalSpace | It is used to store the file attributes. |
Some other comparisons are:
- The File class is more object-oriented than the Path class.
- Path API based I/O stream is less expensive than the File class, from the GC point of view.
- Often, the Path class throws the IOException and returns a Boolean value when any operation is done.