Added in API level 1

File

open class File : Comparable<File!>, Serializable

kotlin.Any
↳	java.io.File

An abstract representation of file and directory pathnames.

User interfaces and operating systems use system-dependent pathname strings to name files and directories. This class presents an abstract, system-independent view of hierarchical pathnames. An abstract pathname has two components:

1. An optional system-dependent prefix string, such as a disk-drive specifier, "/" for the UNIX root directory, or "\\\\" for a Microsoft Windows UNC pathname, and
2. A sequence of zero or more string names.

The first name in an abstract pathname may be a directory name or, in the case of Microsoft Windows UNC pathnames, a hostname. Each subsequent name in an abstract pathname denotes a directory; the last name may denote either a directory or a file. The empty abstract pathname has no prefix and an empty name sequence.

The conversion of a pathname string to or from an abstract pathname is inherently system-dependent. When an abstract pathname is converted into a pathname string, each name is separated from the next by a single copy of the default separator character. The default name-separator character is defined by the system property file.separator, and is made available in the public static fields separator and separatorChar of this class. When a pathname string is converted into an abstract pathname, the names within it may be separated by the default name-separator character or by any other name-separator character that is supported by the underlying system.

A pathname, whether abstract or in string form, may be either absolute or relative. An absolute pathname is complete in that no other information is required in order to locate the file that it denotes. A relative pathname, in contrast, must be interpreted in terms of information taken from some other pathname. By default the classes in the java.io package always resolve relative pathnames against the current user directory. This directory is named by the system property user.dir, and is typically the directory in which the Java virtual machine was invoked.

The parent of an abstract pathname may be obtained by invoking the getParent method of this class and consists of the pathname's prefix and each name in the pathname's name sequence except for the last. Each directory's absolute pathname is an ancestor of any File object with an absolute abstract pathname which begins with the directory's absolute pathname. For example, the directory denoted by the abstract pathname "/usr" is an ancestor of the directory denoted by the pathname "/usr/local/bin".

The prefix concept is used to handle root directories on UNIX platforms, and drive specifiers, root directories and UNC pathnames on Microsoft Windows platforms, as follows:

• For UNIX platforms, the prefix of an absolute pathname is always "/". Relative pathnames have no prefix. The abstract pathname denoting the root directory has the prefix "/" and an empty name sequence.
• For Microsoft Windows platforms, the prefix of a pathname that contains a drive specifier consists of the drive letter followed by ":" and possibly followed by "\\" if the pathname is absolute. The prefix of a UNC pathname is "\\\\"; the hostname and the share name are the first two names in the name sequence. A relative pathname that does not specify a drive has no prefix.

Instances of this class may or may not denote an actual file-system object such as a file or a directory. If it does denote such an object then that object resides in a partition. A partition is an operating system-specific portion of storage for a file system. A single storage device (e.g. a physical disk-drive, flash memory, CD-ROM) may contain multiple partitions. The object, if any, will reside on the partition named by some ancestor of the absolute form of this pathname.

A file system may implement restrictions to certain operations on the actual file-system object, such as reading, writing, and executing. These restrictions are collectively known as access permissions. The file system may have multiple sets of access permissions on a single object. For example, one set may apply to the object's owner, and another may apply to all other users. The access permissions on an object may cause some methods in this class to fail.

Instances of the File class are immutable; that is, once created, the abstract pathname represented by a File object will never change.

Interoperability with java.nio.file package

The java.nio.file package defines interfaces and classes for the Java virtual machine to access files, file attributes, and file systems. This API may be used to overcome many of the limitations of the java.io.File class. The toPath method may be used to obtain a Path that uses the abstract path represented by a File object to locate a file. The resulting Path may be used with the class to provide more efficient and extensive access to additional file operations, file attributes, and I/O exceptions to help diagnose errors when an operation on a file fails.

On Android strings are converted to UTF-8 byte sequences when sending filenames to the operating system, and byte sequences returned by the operating system (from the various list methods) are converted to strings by decoding them as UTF-8 byte sequences.

Summary

Public constructors
File(parent: File?, child: String) Creates a new File instance from a parent abstract pathname and a child pathname string.
File(pathname: String) Creates a new File instance by converting the given pathname string into an abstract pathname.
File(parent: String?, child: String) Creates a new File instance from a parent pathname string and a child pathname string.
File(uri: URI) Creates a new File instance by converting the given URI into an abstract pathname.

Public methods
open Boolean	canExecute() Tests whether the application can execute the file denoted by this abstract pathname.
open Boolean	canRead() Tests whether the application can read the file denoted by this abstract pathname.
open Boolean	canWrite() Tests whether the application can modify the file denoted by this abstract pathname.
open Int	compareTo(other: File) Compares two abstract pathnames lexicographically.
open Boolean	createNewFile() Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist.
open static File	createTempFile(prefix: String, suffix: String?) Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name.
open static File	createTempFile(prefix: String, suffix: String?, directory: File?) Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name.
open Boolean	delete() Deletes the file or directory denoted by this abstract pathname.
open Unit	deleteOnExit() Requests that the file or directory denoted by this abstract pathname be deleted when the virtual machine terminates.
open Boolean	equals(other: Any?) Tests this abstract pathname for equality with the given object.
open Boolean	exists() Tests whether the file or directory denoted by this abstract pathname exists.
open File	getAbsoluteFile() Returns the absolute form of this abstract pathname.
open String	getAbsolutePath() Returns the absolute path of this file.
open File	getCanonicalFile() Returns the canonical form of this abstract pathname.
open String	getCanonicalPath() Returns the canonical pathname string of this abstract pathname.
open Long	getFreeSpace() Returns the number of unallocated bytes in the partition named by this abstract path name.
open String	getName() Returns the name of the file or directory denoted by this abstract pathname.
open String?	getParent() Returns the pathname string of this abstract pathname's parent, or null if this pathname does not name a parent directory.
open File?	getParentFile() Returns the abstract pathname of this abstract pathname's parent, or null if this pathname does not name a parent directory.
open String	getPath() Converts this abstract pathname into a pathname string.
open Long	getTotalSpace() Returns the size of the partition named by this abstract pathname.
open Long	getUsableSpace() Returns the number of bytes available to this virtual machine on the partition named by this abstract pathname.
open Int	hashCode() Computes a hash code for this abstract pathname.
open Boolean	isAbsolute() Tests whether this abstract pathname is absolute.
open Boolean	isDirectory() Tests whether the file denoted by this abstract pathname is a directory.
open Boolean	isFile() Tests whether the file denoted by this abstract pathname is a normal file.
open Boolean	isHidden() Tests whether the file named by this abstract pathname is a hidden file.
open Long	lastModified() Returns the time that the file denoted by this abstract pathname was last modified.
open Long	length() Returns the length of the file denoted by this abstract pathname.
open Array<String!>?	list() Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname.
open Array<String!>?	list(filter: FilenameFilter?) Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
open Array<File!>?	listFiles() Returns an array of abstract pathnames denoting the files in the directory denoted by this abstract pathname.
open Array<File!>?	listFiles(filter: FileFilter?) Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
open Array<File!>?	listFiles(filter: FilenameFilter?) Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
open static Array<File!>	listRoots() Returns the file system roots.
open Boolean	mkdir() Creates the directory named by this abstract pathname.
open Boolean	mkdirs() Creates the directory named by this abstract pathname, including any necessary but nonexistent parent directories.
open Boolean	renameTo(dest: File) Renames the file denoted by this abstract pathname.
open Boolean	setExecutable(executable: Boolean) A convenience method to set the owner's execute permission for this abstract pathname.
open Boolean	setExecutable(executable: Boolean, ownerOnly: Boolean) Sets the owner's or everybody's execute permission for this abstract pathname.
open Boolean	setLastModified(time: Long) Sets the last-modified time of the file or directory named by this abstract pathname.
open Boolean	setReadOnly() Marks the file or directory named by this abstract pathname so that only read operations are allowed.
open Boolean	setReadable(readable: Boolean) A convenience method to set the owner's read permission for this abstract pathname.
open Boolean	setReadable(readable: Boolean, ownerOnly: Boolean) Sets the owner's or everybody's read permission for this abstract pathname.
open Boolean	setWritable(writable: Boolean) A convenience method to set the owner's write permission for this abstract pathname.
open Boolean	setWritable(writable: Boolean, ownerOnly: Boolean) Sets the owner's or everybody's write permission for this abstract pathname.
open Path	toPath() Returns a java.nio.file.Path object constructed from the this abstract path.
open String	toString() Returns the pathname string of this abstract pathname.
open URI	toURI() Constructs a URI that represents this abstract pathname.
open URL	toURL() Converts this abstract pathname into a file: URL.

Properties
static String	pathSeparator The system-dependent path-separator character, represented as a string for convenience.
static Char	pathSeparatorChar The system-dependent path-separator character.
static String	separator The system-dependent default name-separator character, represented as a string for convenience.
static Char	separatorChar The system-dependent default name-separator character.

Public constructors

File

Added in API level 1

File(
    parent: File?, 
    child: String)

Creates a new File instance from a parent abstract pathname and a child pathname string.

If parent is null then the new File instance is created as if by invoking the single-argument File constructor on the given child pathname string.

Otherwise the parent abstract pathname is taken to denote a directory, and the child pathname string is taken to denote either a directory or a file. If the child pathname string is absolute then it is converted into a relative pathname in a system-dependent way. If parent is the empty abstract pathname then the new File instance is created by converting child into an abstract pathname and resolving the result against a system-dependent default directory. Otherwise each pathname string is converted into an abstract pathname and the child abstract pathname is resolved against the parent.

Parameters
parent	File?: The parent abstract pathname
child	String: The child pathname string

Exceptions
java.lang.NullPointerException	If child is null

File

Added in API level 1

File(pathname: String)

Creates a new File instance by converting the given pathname string into an abstract pathname. If the given string is the empty string, then the result is the empty abstract pathname.

Parameters
pathname	String: A pathname string

Exceptions
java.lang.NullPointerException	If the pathname argument is null

File

Added in API level 1

File(
    parent: String?, 
    child: String)

Creates a new File instance from a parent pathname string and a child pathname string.

If parent is null then the new File instance is created as if by invoking the single-argument File constructor on the given child pathname string.

Otherwise the parent pathname string is taken to denote a directory, and the child pathname string is taken to denote either a directory or a file. If the child pathname string is absolute then it is converted into a relative pathname in a system-dependent way. If parent is the empty string then the new File instance is created by converting child into an abstract pathname and resolving the result against a system-dependent default directory. Otherwise each pathname string is converted into an abstract pathname and the child abstract pathname is resolved against the parent.

Parameters
parent	String?: The parent pathname string
child	String: The child pathname string

Exceptions
java.lang.NullPointerException	If child is null

File

Added in API level 1

File(uri: URI)

Creates a new File instance by converting the given URI into an abstract pathname.

The exact form of a file: URI is system-dependent, hence the transformation performed by this constructor is also system-dependent.

For a given abstract pathname f it is guaranteed that

new File( f.toURI()).equals( f.getAbsoluteFile()) so long as the original abstract pathname, the URI, and the new abstract pathname are all created in (possibly different invocations of) the same Java virtual machine. This relationship typically does not hold, however, when a file: URI that is created in a virtual machine on one operating system is converted into an abstract pathname in a virtual machine on a different operating system.

Parameters
uri	URI: An absolute, hierarchical URI with a scheme equal to "file", a non-empty path component, and undefined authority, query, and fragment components

Exceptions
java.lang.NullPointerException	If uri is null
java.lang.IllegalArgumentException	If the preconditions on the parameter do not hold

See Also

• #toURI()
• java.net.URI

Public methods

canExecute

Added in API level 9

open fun canExecute(): Boolean

Tests whether the application can execute the file denoted by this abstract pathname.

Return
Boolean	true if and only if the abstract pathname exists and the application is allowed to execute the file

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkExec(java.lang.String) method denies execute access to the file

canRead

Added in API level 1

open fun canRead(): Boolean

Tests whether the application can read the file denoted by this abstract pathname.

Return
Boolean	true if and only if the file specified by this abstract pathname exists and can be read by the application; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file

canWrite

Added in API level 1

open fun canWrite(): Boolean

Tests whether the application can modify the file denoted by this abstract pathname.

Return
Boolean	true if and only if the file system actually contains a file denoted by this abstract pathname and the application is allowed to write to the file; false otherwise.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

compareTo

Added in API level 1

open fun compareTo(other: File): Int

Compares two abstract pathnames lexicographically. The ordering defined by this method depends upon the underlying system. On UNIX systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows systems it is not.

Parameters
o	the object to be compared.
pathname	The abstract pathname to be compared to this abstract pathname

Return
Int	Zero if the argument is equal to this abstract pathname, a value less than zero if this abstract pathname is lexicographically less than the argument, or a value greater than zero if this abstract pathname is lexicographically greater than the argument

Exceptions
java.lang.NullPointerException	if the specified object is null
java.lang.ClassCastException	if the specified object's type prevents it from being compared to this object.

createNewFile

Added in API level 1

open fun createNewFile(): Boolean

Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist. The check for the existence of the file and the creation of the file if it does not exist are a single operation that is atomic with respect to all other filesystem activities that might affect the file.

Note: this method should not be used for file-locking, as the resulting protocol cannot be made to work reliably. The FileLock facility should be used instead.

Return
Boolean	true if the named file does not exist and was successfully created; false if the named file already exists

Exceptions
java.io.IOException	If an I/O error occurred
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

createTempFile

Added in API level 1

open static fun createTempFile(
    prefix: String, 
    suffix: String?
): File

Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name. Invoking this method is equivalent to invoking createTempFile(prefix, suffix, null).

The Files.createTempFile method provides an alternative method to create an empty file in the temporary-file directory. Files created by that method may have more restrictive access permissions to files created by this method and so may be more suited to security-sensitive applications.

Parameters
prefix	String: The prefix string to be used in generating the file's name; must be at least three characters long
suffix	String?: The suffix string to be used in generating the file's name; may be null, in which case the suffix ".tmp" will be used

Return
File	An abstract pathname denoting a newly-created empty file

Exceptions
java.lang.IllegalArgumentException	If the prefix argument contains fewer than three characters
java.io.IOException	If a file could not be created
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method does not allow a file to be created

See Also

createTempFile

Added in API level 1

open static fun createTempFile(
    prefix: String, 
    suffix: String?, 
    directory: File?
): File

Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name. If this method returns successfully then it is guaranteed that:

1. The file denoted by the returned abstract pathname did not exist before this method was invoked, and
2. Neither this method nor any of its variants will return the same abstract pathname again in the current invocation of the virtual machine.

This method provides only part of a temporary-file facility. To arrange for a file created by this method to be deleted automatically, use the deleteOnExit method.

The prefix argument must be at least three characters long. It is recommended that the prefix be a short, meaningful string such as "hjb" or "mail". The suffix argument may be null, in which case the suffix ".tmp" will be used.

To create the new file, the prefix and the suffix may first be adjusted to fit the limitations of the underlying platform. If the prefix is too long then it will be truncated, but its first three characters will always be preserved. If the suffix is too long then it too will be truncated, but if it begins with a period character ('.') then the period and the first three characters following it will always be preserved. Once these adjustments have been made the name of the new file will be generated by concatenating the prefix, five or more internally-generated characters, and the suffix.

If the directory argument is null then the system-dependent default temporary-file directory will be used. The default temporary-file directory is specified by the system property java.io.tmpdir. On UNIX systems the default value of this property is typically "/tmp" or "/var/tmp"; on Microsoft Windows systems it is typically "C:\\WINNT\\TEMP". A different value may be given to this system property when the Java virtual machine is invoked, but programmatic changes to this property are not guaranteed to have any effect upon the temporary directory used by this method.

Parameters
prefix	String: The prefix string to be used in generating the file's name; must be at least three characters long
suffix	String?: The suffix string to be used in generating the file's name; may be null, in which case the suffix ".tmp" will be used
directory	File?: The directory in which the file is to be created, or null if the default temporary-file directory is to be used

Return
File	An abstract pathname denoting a newly-created empty file

Exceptions
java.lang.IllegalArgumentException	If the prefix argument contains fewer than three characters
java.io.IOException	If a file could not be created
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method does not allow a file to be created

delete

Added in API level 1

open fun delete(): Boolean

Deletes the file or directory denoted by this abstract pathname. If this pathname denotes a directory, then the directory must be empty in order to be deleted.

Note that the java.nio.file.Files class defines the delete method to throw an IOException when a file cannot be deleted. This is useful for error reporting and to diagnose why a file cannot be deleted.

Return
Boolean	true if and only if the file or directory is successfully deleted; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkDelete method denies delete access to the file

deleteOnExit

Added in API level 1

open fun deleteOnExit(): Unit

Requests that the file or directory denoted by this abstract pathname be deleted when the virtual machine terminates. Files (or directories) are deleted in the reverse order that they are registered. Invoking this method to delete a file or directory that is already registered for deletion has no effect. Deletion will be attempted only for normal termination of the virtual machine, as defined by the Java Language Specification.

Once deletion has been requested, it is not possible to cancel the request. This method should therefore be used with care.

Note: this method should not be used for file-locking, as the resulting protocol cannot be made to work reliably. The FileLock facility should be used instead.

Note that on Android, the application lifecycle does not include VM termination, so calling this method will not ensure that files are deleted. Instead, you should use the most appropriate out of:

• Use a finally clause to manually invoke delete.
• Maintain your own set of files to delete, and process it at an appropriate point in your application's lifecycle.
• Use the Unix trick of deleting the file as soon as all readers and writers have opened it. No new readers/writers will be able to access the file, but all existing ones will still have access until the last one closes the file.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkDelete method denies delete access to the file

See Also

• #delete

equals

Added in API level 1

open fun equals(other: Any?): Boolean

Tests this abstract pathname for equality with the given object. Returns true if and only if the argument is not null and is an abstract pathname that denotes the same file or directory as this abstract pathname. Whether or not two abstract pathnames are equal depends upon the underlying system. On UNIX systems, alphabetic case is significant in comparing pathnames; on Microsoft Windows systems it is not.

Parameters
obj	The object to be compared with this abstract pathname

Return
Boolean	true if and only if the objects are the same; false otherwise

exists

Added in API level 1

open fun exists(): Boolean

Tests whether the file or directory denoted by this abstract pathname exists.

Return
Boolean	true if and only if the file or directory denoted by this abstract pathname exists; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file or directory

getAbsoluteFile

Added in API level 1

open fun getAbsoluteFile(): File

Returns the absolute form of this abstract pathname. Equivalent to new File(this.getAbsolutePath).

Return
File	The absolute abstract pathname denoting the same file or directory as this abstract pathname

Exceptions
java.lang.SecurityException	If a required system property value cannot be accessed.

getAbsolutePath

Added in API level 1

open fun getAbsolutePath(): String

Returns the absolute path of this file. An absolute path is a path that starts at a root of the file system. On Android, there is only one root: /.

A common use for absolute paths is when passing paths to a Process as command-line arguments, to remove the requirement implied by relative paths, that the child must have the same working directory as its parent.

Return
String	The absolute pathname string denoting the same file or directory as this abstract pathname

See Also

• java.io.File#isAbsolute()

getCanonicalFile

Added in API level 1

open fun getCanonicalFile(): File

Returns the canonical form of this abstract pathname. Equivalent to new File(this.getCanonicalPath).

Return
File	The canonical pathname string denoting the same file or directory as this abstract pathname

Exceptions
java.io.IOException	If an I/O error occurs, which is possible because the construction of the canonical pathname may require filesystem queries
java.lang.SecurityException	If a required system property value cannot be accessed, or if a security manager exists and its java.lang.SecurityManager#checkRead method denies read access to the file

See Also

• java.nio.file.Path#toRealPath

getCanonicalPath

Added in API level 1

open fun getCanonicalPath(): String

Returns the canonical pathname string of this abstract pathname.

A canonical pathname is both absolute and unique. The precise definition of canonical form is system-dependent. This method first converts this pathname to absolute form if necessary, as if by invoking the getAbsolutePath method, and then maps it to its unique form in a system-dependent way. This typically involves removing redundant names such as "." and ".." from the pathname, resolving symbolic links (on UNIX platforms), and converting drive letters to a standard case (on Microsoft Windows platforms).

Every pathname that denotes an existing file or directory has a unique canonical form. Every pathname that denotes a nonexistent file or directory also has a unique canonical form. The canonical form of the pathname of a nonexistent file or directory may be different from the canonical form of the same pathname after the file or directory is created. Similarly, the canonical form of the pathname of an existing file or directory may be different from the canonical form of the same pathname after the file or directory is deleted.

Return
String	The canonical pathname string denoting the same file or directory as this abstract pathname

Exceptions
java.io.IOException	If an I/O error occurs, which is possible because the construction of the canonical pathname may require filesystem queries
java.lang.SecurityException	If a required system property value cannot be accessed, or if a security manager exists and its java.lang.SecurityManager#checkRead method denies read access to the file

See Also

• java.nio.file.Path#toRealPath

getFreeSpace

Added in API level 9

open fun getFreeSpace(): Long

Returns the number of unallocated bytes in the partition named by this abstract path name.

The returned number of unallocated bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of unallocated bytes is most likely to be accurate immediately after this call. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this virtual machine. This method makes no guarantee that write operations to this file system will succeed.

Return
Long	The number of unallocated bytes on the partition or 0L if the abstract pathname does not name a partition. This value will be less than or equal to the total file system size returned by getTotalSpace.

Exceptions
java.lang.SecurityException	If a security manager has been installed and it denies RuntimePermission("getFileSystemAttributes") or its SecurityManager.checkRead(String) method denies read access to the file named by this abstract pathname

getName

Added in API level 1

open fun getName(): String

Returns the name of the file or directory denoted by this abstract pathname. This is just the last name in the pathname's name sequence. If the pathname's name sequence is empty, then the empty string is returned.

Return
String	The name of the file or directory denoted by this abstract pathname, or the empty string if this pathname's name sequence is empty

getParent

Added in API level 1

open fun getParent(): String?

Returns the pathname string of this abstract pathname's parent, or null if this pathname does not name a parent directory.

The parent of an abstract pathname consists of the pathname's prefix, if any, and each name in the pathname's name sequence except for the last. If the name sequence is empty then the pathname does not name a parent directory.

Return
String?	The pathname string of the parent directory named by this abstract pathname, or null if this pathname does not name a parent

getParentFile

Added in API level 1

open fun getParentFile(): File?

Returns the abstract pathname of this abstract pathname's parent, or null if this pathname does not name a parent directory.

The parent of an abstract pathname consists of the pathname's prefix, if any, and each name in the pathname's name sequence except for the last. If the name sequence is empty then the pathname does not name a parent directory.

Return
File?	The abstract pathname of the parent directory named by this abstract pathname, or null if this pathname does not name a parent

getPath

Added in API level 1

open fun getPath(): String

Converts this abstract pathname into a pathname string. The resulting string uses the default name-separator character to separate the names in the name sequence.

Return
String	The string form of this abstract pathname

getTotalSpace

Added in API level 9

open fun getTotalSpace(): Long

Returns the size of the partition named by this abstract pathname.

Return
Long	The size, in bytes, of the partition or 0L if this abstract pathname does not name a partition

Exceptions
java.lang.SecurityException	If a security manager has been installed and it denies RuntimePermission("getFileSystemAttributes") or its SecurityManager.checkRead(String) method denies read access to the file named by this abstract pathname

getUsableSpace

Added in API level 9

open fun getUsableSpace(): Long

Returns the number of bytes available to this virtual machine on the partition named by this abstract pathname. When possible, this method checks for write permissions and other operating system restrictions and will therefore usually provide a more accurate estimate of how much new data can actually be written than getFreeSpace.

The returned number of available bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of unallocated bytes is most likely to be accurate immediately after this call. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this virtual machine. This method makes no guarantee that write operations to this file system will succeed.

On Android (and other Unix-based systems), this method returns the number of free bytes available to non-root users, regardless of whether you're actually running as root, and regardless of any quota or other restrictions that might apply to the user. (The getFreeSpace method returns the number of bytes potentially available to root.)

Return
Long	The number of available bytes on the partition or 0L if the abstract pathname does not name a partition. On systems where this information is not available, this method will be equivalent to a call to getFreeSpace.

Exceptions
java.lang.SecurityException	If a security manager has been installed and it denies RuntimePermission("getFileSystemAttributes") or its SecurityManager.checkRead(String) method denies read access to the file named by this abstract pathname

hashCode

Added in API level 1

open fun hashCode(): Int

Computes a hash code for this abstract pathname. Because equality of abstract pathnames is inherently system-dependent, so is the computation of their hash codes. On UNIX systems, the hash code of an abstract pathname is equal to the exclusive or of the hash code of its pathname string and the decimal value 1234321. On Microsoft Windows systems, the hash code is equal to the exclusive or of the hash code of its pathname string converted to lower case and the decimal value 1234321. Locale is not taken into account on lowercasing the pathname string.

Return
Int	A hash code for this abstract pathname

isAbsolute

Added in API level 1

open fun isAbsolute(): Boolean

Tests whether this abstract pathname is absolute. The definition of absolute pathname is system dependent. On Android, absolute paths start with the character '/'.

Return
Boolean	true if this abstract pathname is absolute, false otherwise

isDirectory

Added in API level 1

open fun isDirectory(): Boolean

Tests whether the file denoted by this abstract pathname is a directory.

Where it is required to distinguish an I/O exception from the case that the file is not a directory, or where several attributes of the same file are required at the same time, then the java.nio.file.Files#readAttributes(Path,Class,LinkOption[]) method may be used.

Return
Boolean	true if and only if the file denoted by this abstract pathname exists and is a directory; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file

isFile

Added in API level 1

open fun isFile(): Boolean

Tests whether the file denoted by this abstract pathname is a normal file. A file is normal if it is not a directory and, in addition, satisfies other system-dependent criteria. Any non-directory file created by a Java application is guaranteed to be a normal file.

Where it is required to distinguish an I/O exception from the case that the file is not a normal file, or where several attributes of the same file are required at the same time, then the java.nio.file.Files#readAttributes(Path,Class,LinkOption[]) method may be used.

Return
Boolean	true if and only if the file denoted by this abstract pathname exists and is a normal file; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file

isHidden

Added in API level 1

open fun isHidden(): Boolean

Tests whether the file named by this abstract pathname is a hidden file. The exact definition of hidden is system-dependent. On UNIX systems, a file is considered to be hidden if its name begins with a period character ('.'). On Microsoft Windows systems, a file is considered to be hidden if it has been marked as such in the filesystem.

Return
Boolean	true if and only if the file denoted by this abstract pathname is hidden according to the conventions of the underlying platform

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file

lastModified

Added in API level 1

open fun lastModified(): Long

Returns the time that the file denoted by this abstract pathname was last modified.

Where it is required to distinguish an I/O exception from the case where 0L is returned, or where several attributes of the same file are required at the same time, or where the time of last access or the creation time are required, then the java.nio.file.Files#readAttributes(Path,Class,LinkOption[]) method may be used.

Return
Long	A long value representing the time the file was last modified, measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970), or 0L if the file does not exist or if an I/O error occurs

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file

length

Added in API level 1

open fun length(): Long

Returns the length of the file denoted by this abstract pathname. The return value is unspecified if this pathname denotes a directory.

Where it is required to distinguish an I/O exception from the case that 0L is returned, or where several attributes of the same file are required at the same time, then the java.nio.file.Files#readAttributes(Path,Class,LinkOption[]) method may be used.

Return
Long	The length, in bytes, of the file denoted by this abstract pathname, or 0L if the file does not exist. Some operating systems may return 0L for pathnames denoting system-dependent entities such as devices or pipes.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the file

list

Added in API level 1

open fun list(): Array<String!>?

Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname.

If this abstract pathname does not denote a directory, then this method returns null. Otherwise an array of strings is returned, one for each file or directory in the directory. Names denoting the directory itself and the directory's parent directory are not included in the result. Each string is a file name rather than a complete path.

There is no guarantee that the name strings in the resulting array will appear in any specific order; they are not, in particular, guaranteed to appear in alphabetical order.

Note that the java.nio.file.Files class defines the newDirectoryStream method to open a directory and iterate over the names of the files in the directory. This may use less resources when working with very large directories, and may be more responsive when working with remote directories.

Return
Array<String!>?	An array of strings naming the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the directory

list

Added in API level 1

open fun list(filter: FilenameFilter?): Array<String!>?

Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter. The behavior of this method is the same as that of the list() method, except that the strings in the returned array must satisfy the filter. If the given filter is null then all names are accepted. Otherwise, a name satisfies the filter if and only if the value true results when the FilenameFilter.accept(File, String) method of the filter is invoked on this abstract pathname and the name of a file or directory in the directory that it denotes.

Parameters
filter	FilenameFilter?: A filename filter

Return
Array<String!>?	An array of strings naming the files and directories in the directory denoted by this abstract pathname that were accepted by the given filter. The array will be empty if the directory is empty or if no names were accepted by the filter. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the directory

See Also

• java.nio.file.Files#newDirectoryStream(Path,String)

listFiles

Added in API level 1

open fun listFiles(): Array<File!>?

Returns an array of abstract pathnames denoting the files in the directory denoted by this abstract pathname.

If this abstract pathname does not denote a directory, then this method returns null. Otherwise an array of File objects is returned, one for each file or directory in the directory. Pathnames denoting the directory itself and the directory's parent directory are not included in the result. Each resulting abstract pathname is constructed from this abstract pathname using the File(File, String) constructor. Therefore if this pathname is absolute then each resulting pathname is absolute; if this pathname is relative then each resulting pathname will be relative to the same directory.

There is no guarantee that the name strings in the resulting array will appear in any specific order; they are not, in particular, guaranteed to appear in alphabetical order.

Note that the java.nio.file.Files class defines the newDirectoryStream method to open a directory and iterate over the names of the files in the directory. This may use less resources when working with very large directories.

Return
Array<File!>?	An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the directory

listFiles

Added in API level 1

open fun listFiles(filter: FileFilter?): Array<File!>?

Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter. The behavior of this method is the same as that of the listFiles() method, except that the pathnames in the returned array must satisfy the filter. If the given filter is null then all pathnames are accepted. Otherwise, a pathname satisfies the filter if and only if the value true results when the FileFilter.accept(File) method of the filter is invoked on the pathname.

Parameters
filter	FileFilter?: A file filter

Return
Array<File!>?	An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the directory

See Also

• java.nio.file.Files#newDirectoryStream(Path,java.nio.file.DirectoryStream.Filter)

listFiles

Added in API level 1

open fun listFiles(filter: FilenameFilter?): Array<File!>?

Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter. The behavior of this method is the same as that of the listFiles() method, except that the pathnames in the returned array must satisfy the filter. If the given filter is null then all pathnames are accepted. Otherwise, a pathname satisfies the filter if and only if the value true results when the FilenameFilter.accept(File, String) method of the filter is invoked on this abstract pathname and the name of a file or directory in the directory that it denotes.

Parameters
filter	FilenameFilter?: A filename filter

Return
Array<File!>?	An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method denies read access to the directory

See Also

• java.nio.file.Files#newDirectoryStream(Path,String)

listRoots

Added in API level 1

open static fun listRoots(): Array<File!>

Returns the file system roots. On Android and other Unix systems, there is a single root, /.

mkdir

Added in API level 1

open fun mkdir(): Boolean

Creates the directory named by this abstract pathname.

Return
Boolean	true if and only if the directory was created; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method does not permit the named directory to be created

mkdirs

Added in API level 1

open fun mkdirs(): Boolean

Creates the directory named by this abstract pathname, including any necessary but nonexistent parent directories. Note that if this operation fails it may have succeeded in creating some of the necessary parent directories.

Return
Boolean	true if and only if the directory was created, along with all necessary parent directories; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkRead(java.lang.String) method does not permit verification of the existence of the named directory and all necessary parent directories; or if the java.lang.SecurityManager#checkWrite(java.lang.String) method does not permit the named directory and all necessary parent directories to be created

renameTo

Added in API level 1

open fun renameTo(dest: File): Boolean

Renames the file denoted by this abstract pathname.

Many failures are possible. Some of the more likely failures include:

• Write permission is required on the directories containing both the source and destination paths.
• Search permission is required for all parents of both paths.
• Both paths be on the same mount point. On Android, applications are most likely to hit this restriction when attempting to copy between internal storage and an SD card.

The return value should always be checked to make sure that the rename operation was successful.

Note that the java.nio.file.Files class defines the move method to move or rename a file in a platform independent manner.

Parameters
dest	File: The new abstract pathname for the named file

Return
Boolean	true if and only if the renaming succeeded; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to either the old or new pathnames
java.lang.NullPointerException	If parameter dest is null

setExecutable

Added in API level 9

open fun setExecutable(executable: Boolean): Boolean

A convenience method to set the owner's execute permission for this abstract pathname.

An invocation of this method of the form file.setExcutable(arg) behaves in exactly the same way as the invocation

file.setExecutable(arg, true) 

Parameters
executable	Boolean: If true, sets the access permission to allow execute operations; if false to disallow execute operations

Return
Boolean	true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If executable is false and the underlying file system does not implement an execute permission, then the operation will fail.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

setExecutable

Added in API level 9

open fun setExecutable(
    executable: Boolean, 
    ownerOnly: Boolean
): Boolean

Sets the owner's or everybody's execute permission for this abstract pathname.

The java.nio.file.Files class defines methods that operate on file attributes including file permissions. This may be used when finer manipulation of file permissions is required.

Parameters
executable	Boolean: If true, sets the access permission to allow execute operations; if false to disallow execute operations
ownerOnly	Boolean: If true, the execute permission applies only to the owner's execute permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's execute permission from that of others, then the permission will apply to everybody, regardless of this value.

Return
Boolean	true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If executable is false and the underlying file system does not implement an execute permission, then the operation will fail.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

setLastModified

Added in API level 1

open fun setLastModified(time: Long): Boolean

Sets the last-modified time of the file or directory named by this abstract pathname.

All platforms support file-modification times to the nearest second, but some provide more precision. The argument will be truncated to fit the supported precision. If the operation succeeds and no intervening operations on the file take place, then the next invocation of the lastModified method will return the (possibly truncated) time argument that was passed to this method.

Parameters
time	Long: The new last-modified time, measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970)

Return
Boolean	true if and only if the operation succeeded; false otherwise

Exceptions
java.lang.IllegalArgumentException	If the argument is negative
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the named file

setReadOnly

Added in API level 1

open fun setReadOnly(): Boolean

Marks the file or directory named by this abstract pathname so that only read operations are allowed. After invoking this method the file or directory will not change until it is either deleted or marked to allow write access. Whether or not a read-only file or directory may be deleted depends upon the underlying system.

Return
Boolean	true if and only if the operation succeeded; false otherwise

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the named file

setReadable

Added in API level 9

open fun setReadable(readable: Boolean): Boolean

A convenience method to set the owner's read permission for this abstract pathname.

An invocation of this method of the form file.setReadable(arg) behaves in exactly the same way as the invocation

file.setReadable(arg, true) 

Parameters
readable	Boolean: If true, sets the access permission to allow read operations; if false to disallow read operations

Return
Boolean	true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If readable is false and the underlying file system does not implement a read permission, then the operation will fail.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

setReadable

Added in API level 9

open fun setReadable(
    readable: Boolean, 
    ownerOnly: Boolean
): Boolean

Sets the owner's or everybody's read permission for this abstract pathname.

The java.nio.file.Files class defines methods that operate on file attributes including file permissions. This may be used when finer manipulation of file permissions is required.

Parameters
readable	Boolean: If true, sets the access permission to allow read operations; if false to disallow read operations
ownerOnly	Boolean: If true, the read permission applies only to the owner's read permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's read permission from that of others, then the permission will apply to everybody, regardless of this value.

Return
Boolean	true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname. If readable is false and the underlying file system does not implement a read permission, then the operation will fail.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

setWritable

Added in API level 9

open fun setWritable(writable: Boolean): Boolean

A convenience method to set the owner's write permission for this abstract pathname.

An invocation of this method of the form file.setWritable(arg) behaves in exactly the same way as the invocation

file.setWritable(arg, true) 

Parameters
writable	Boolean: If true, sets the access permission to allow write operations; if false to disallow write operations

Return
Boolean	true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the file

setWritable

Added in API level 9

open fun setWritable(
    writable: Boolean, 
    ownerOnly: Boolean
): Boolean

Sets the owner's or everybody's write permission for this abstract pathname.

The java.nio.file.Files class defines methods that operate on file attributes including file permissions. This may be used when finer manipulation of file permissions is required.

Parameters
writable	Boolean: If true, sets the access permission to allow write operations; if false to disallow write operations
ownerOnly	Boolean: If true, the write permission applies only to the owner's write permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's write permission from that of others, then the permission will apply to everybody, regardless of this value.

Return
Boolean	true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname.

Exceptions
java.lang.SecurityException	If a security manager exists and its java.lang.SecurityManager#checkWrite(java.lang.String) method denies write access to the named file

toPath

Added in API level 26

open fun toPath(): Path

Returns a java.nio.file.Path object constructed from the this abstract path. The resulting is associated with the default-filesystem

The first invocation of this method works as if invoking it were equivalent to evaluating the expression:

<code><a docref="java.nio.file.FileSystems$getDefault()">FileSystems.getDefault</a></code>().<code><a docref="java.nio.file.FileSystem$getPath(kotlin.String, kotlin.Array((kotlin.String)))">getPath</a></code>(this.<code><a docref="java.io.File$getPath()">getPath</a></code>());
  

Subsequent invocations of this method return the same Path.

If this abstract pathname is the empty abstract pathname then this method returns a Path that may be used to access the current user directory.

Return
Path	a Path constructed from this abstract path

Exceptions
java.nio.file.InvalidPathException	if a Path object cannot be constructed from the abstract path (see FileSystem.getPath)

See Also

• java.nio.file.Path#toFile

toString

Added in API level 1

open fun toString(): String

Returns the pathname string of this abstract pathname. This is just the string returned by the getPath method.

Return
String	The string form of this abstract pathname

toURI

Added in API level 1

open fun toURI(): URI

Constructs a URI that represents this abstract pathname.

The exact form of the URI is system-dependent. If it can be determined that the file denoted by this abstract pathname is a directory, then the resulting URI will end with a slash.

For a given abstract pathname f, it is guaranteed that

new File( f.toURI()).equals( f.getAbsoluteFile()) so long as the original abstract pathname, the URI, and the new abstract pathname are all created in (possibly different invocations of) the same Java virtual machine. Due to the system-dependent nature of abstract pathnames, however, this relationship typically does not hold when a file: URI that is created in a virtual machine on one operating system is converted into an abstract pathname in a virtual machine on a different operating system.

Note that when this abstract pathname represents a UNC pathname then all components of the UNC (including the server name component) are encoded in the URI path. The authority component is undefined, meaning that it is represented as null. The Path class defines the toUri method to encode the server name in the authority component of the resulting URI. The toPath method may be used to obtain a Path representing this abstract pathname.

Return
URI	An absolute, hierarchical URI with a scheme equal to "file", a path representing this abstract pathname, and undefined authority, query, and fragment components

Exceptions
java.lang.SecurityException	If a required system property value cannot be accessed.

See Also

• #File(java.net.URI)
• java.net.URI
• java.net.URI#toURL()

toURL

Added in API level 1
Deprecated in API level 15

open fun toURL(): URL

Deprecated: This method does not automatically escape characters that are illegal in URLs. It is recommended that new code convert an abstract pathname into a URL by first converting it into a URI, via the toURI method, and then converting the URI into a URL via the URI.toURL method.

Converts this abstract pathname into a file: URL. The exact form of the URL is system-dependent. If it can be determined that the file denoted by this abstract pathname is a directory, then the resulting URL will end with a slash.

Return
URL	A URL object representing the equivalent file URL

Exceptions
java.net.MalformedURLException	If the path cannot be parsed as a URL

See Also

• #toURI()
• java.net.URI
• java.net.URI#toURL()
• java.net.URL

Properties

pathSeparator

Added in API level 1

static val pathSeparator: String

The system-dependent path-separator character, represented as a string for convenience. This string contains a single character, namely pathSeparatorChar.

pathSeparatorChar

Added in API level 1

static val pathSeparatorChar: Char

The system-dependent path-separator character. This field is initialized to contain the first character of the value of the system property path.separator. This character is used to separate filenames in a sequence of files given as a path list. On UNIX systems, this character is ':'; on Microsoft Windows systems it is ';'.

See Also

• java.lang.System#getProperty(java.lang.String)

separator

Added in API level 1

static val separator: String

The system-dependent default name-separator character, represented as a string for convenience. This string contains a single character, namely separatorChar.

separatorChar

Added in API level 1

static val separatorChar: Char

The system-dependent default name-separator character. This field is initialized to contain the first character of the value of the system property file.separator. On UNIX systems the value of this field is '/'; on Microsoft Windows systems it is '\\'.

See Also

• java.lang.System#getProperty(java.lang.String)