java.util.prefs
Class WindowsPreferences

java.lang.Object
  java.util.prefs.Preferences
      java.util.prefs.AbstractPreferences
          java.util.prefs.WindowsPreferences

class WindowsPreferences

extends AbstractPreferences

Windows registry based implementation of Preferences. Preferences' systemRoot and userRoot are stored in HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Prefs and HKEY_CURRENT_USER\Software\JavaSoft\Prefs correspondingly.

Since:

1.4

Author:

Konstantin Kladko

See Also:

Preferences, PreferencesFactory

Nested Class Summary

Nested classes inherited from class java.util.prefs.AbstractPreferences

Field Summary

private static int	DELETE
private static int	DISPOSITION
private static int	ERROR_ACCESS_DENIED
private static int	ERROR_CODE
private static int	ERROR_FILE_NOT_FOUND
private static int	ERROR_SUCCESS
private static int	HKEY_CURRENT_USER Windows handles to HKEY_CURRENT_USER and HKEY_LOCAL_MACHINE hives.
private static int	HKEY_LOCAL_MACHINE
private static int	INIT_SLEEP_TIME Initial time between registry access attempts, in ms.
private boolean	isBackingStoreAvailable BackingStore availability flag.
private static int	KEY_ALL_ACCESS
private static int	KEY_CREATE_SUB_KEY
private static int	KEY_ENUMERATE_SUB_KEYS
private static int	KEY_QUERY_VALUE
private static int	KEY_READ
private static int	KEY_SET_VALUE
private static int	KEY_WRITE
private static Logger	logger Logger for error messages
private static int	MAX_ATTEMPTS Maximum number of registry access attempts.
private static int	MAX_KEY_LENGTH
private static int	MAX_VALUE_NAME_LENGTH
private static int	MAX_WINDOWS_PATH_LENGTH Maximum byte-encoded path length for Windows native functions, ending null character not included.
private static int	NATIVE_HANDLE
private static int	NULL_NATIVE_HANDLE
private static int	REG_CREATED_NEW_KEY
private static int	REG_OPENED_EXISTING_KEY
private static int	SUBKEYS_NUMBER
private static int	SYSTEM_ROOT_NATIVE_HANDLE Mount point for Preferences' system root.
(package private) static Preferences	systemRoot System root node.
private static int	USER_ROOT_NATIVE_HANDLE Mount point for Preferences' user root.
(package private) static Preferences	userRoot User root node.
private static int	VALUES_NUMBER
private static byte[]	WINDOWS_ROOT_PATH Windows registry path to Preferences's root nodes.

Fields inherited from class java.util.prefs.AbstractPreferences

lock, newNode, parent

Fields inherited from class java.util.prefs.Preferences

MAX_NAME_LENGTH, MAX_VALUE_LENGTH

Constructor Summary

private	WindowsPreferences(int rootNativeHandle, byte[] rootDirectory) Constructs a root node creating the underlying Windows registry node and all of its parents, if they have not yet been created.
private	WindowsPreferences(WindowsPreferences parent, String name) Constructs a WindowsPreferences node, creating underlying Windows registry node and all its Windows parents, if they are not yet created.

Method Summary

private static String	byteArrayToString(byte[] array) Converts a null-terminated byte array to java string
protected String[]	childrenNamesSpi() Implements AbstractPreferences childrenNamesSpi() method.
protected AbstractPreferences	childSpi(String name) Implements AbstractPreferences childSpi() method.
private void	closeKey(int nativeHandle) Closes Windows registry key.
void	flush() Implements Preferences flush() method.
protected void	flushSpi() Empty, never used implementation of AbstractPreferences.flushSpi().
protected String	getSpi(String javaName) Implements AbstractPreferences getSpi() method.
protected String[]	keysSpi() Implements AbstractPreferences keysSpi() method.
private static Logger	logger()
private int	openKey(byte[] windowsAbsolutePath, int mask1, int mask2) Opens Windows registry key at a given absolute path using a given security mask.
private int	openKey(int securityMask) Opens current node's underlying Windows registry key using a given security mask.
private int	openKey(int nativeHandle, byte[] windowsRelativePath, int mask1, int mask2) Opens Windows registry key at a given relative path with respect to a given Windows registry key.
private int	openKey(int mask1, int mask2) Opens current node's underlying Windows registry key using a given security mask.
protected void	putSpi(String javaName, String value) Implements AbstractPreferences putSpi() method.
void	removeNodeSpi() Implements AbstractPreferences removeNodeSpi() method.
protected void	removeSpi(String key) Implements AbstractPreferences removeSpi() method.
private int	rootNativeHandle() Returns native handle for the top Windows node for this node.
private static byte[]	stringToByteArray(String str) Returns this java string as a null-terminated byte array
void	sync() Implements Preferences sync() method.
protected void	syncSpi() Empty, never used implementation of AbstractPreferences.flushSpi().
private static String	toJavaAlt64Name(String windowsName) Converts value's or node's name from its Windows representation to java string, using altBase64 encoding.
private static String	toJavaName(byte[] windowsNameArray) Converts value's or node's name from its byte array representation to java string.
private static String	toJavaValueString(byte[] windowsNameArray) Converts value string from its Windows representation to java string.
private static byte[]	toWindowsAlt64Name(String javaName) Converts value's or node's name to its Windows representation as a byte-encoded string, using altBase64 encoding.
private static byte[]	toWindowsName(String javaName) Converts value's or node's name to its Windows representation as a byte-encoded string.
private static byte[]	toWindowsValueString(String javaName) Converts value string to it Windows representation.
private byte[]	windowsAbsolutePath() Returns Windows absolute path of the current node as a byte array.
private static int	WindowsRegCloseKey(int hKey) Java wrapper for Windows registry API RegCloseKey()
private static int[]	WindowsRegCreateKeyEx(int hKey, byte[] subKey) Java wrapper for Windows registry API RegCreateKeyEx()
private static int[]	WindowsRegCreateKeyEx1(int hKey, byte[] subKey) Retries RegCreateKeyEx() MAX_ATTEMPTS times before giving up.
private static int	WindowsRegDeleteKey(int hKey, byte[] subKey) Java wrapper for Windows registry API RegDeleteKey()
private static int	WindowsRegDeleteValue(int hKey, byte[] valueName) Java wrapper for Windows registry API RegDeleteValue()
private static byte[]	WindowsRegEnumKeyEx(int hKey, int subKeyIndex, int maxKeyLength) Java wrapper for Windows registry API RegEnumKeyEx()
private static byte[]	WindowsRegEnumKeyEx1(int hKey, int subKeyIndex, int maxKeyLength) Retries RegEnumKeyEx() MAX_ATTEMPTS times before giving up.
private static byte[]	WindowsRegEnumValue(int hKey, int valueIndex, int maxValueNameLength) Java wrapper for Windows registry API RegEnumValue()
private static byte[]	WindowsRegEnumValue1(int hKey, int valueIndex, int maxValueNameLength) Retries RegEnumValueEx() MAX_ATTEMPTS times before giving up.
private static int	WindowsRegFlushKey(int hKey) Java wrapper for Windows registry API RegFlushKey()
private static int	WindowsRegFlushKey1(int hKey) Retries RegFlushKey() MAX_ATTEMPTS times before giving up.
private static int[]	WindowsRegOpenKey(int hKey, byte[] subKey, int securityMask) Java wrapper for Windows registry API RegOpenKey()
private static int[]	WindowsRegOpenKey1(int hKey, byte[] subKey, int securityMask) Retries RegOpenKey() MAX_ATTEMPTS times before giving up.
private static int[]	WindowsRegQueryInfoKey(int hKey) Java wrapper for Windows registry API RegQueryInfoKey()
private static int[]	WindowsRegQueryInfoKey1(int hKey) Retries RegQueryInfoKey() MAX_ATTEMPTS times before giving up.
private static byte[]	WindowsRegQueryValueEx(int hKey, byte[] valueName) Java wrapper for Windows registry API RegQueryValueEx()
private static int	WindowsRegSetValueEx(int hKey, byte[] valueName, byte[] value) Java wrapper for Windows registry API RegSetValueEx()
private static int	WindowsRegSetValueEx1(int hKey, byte[] valueName, byte[] value) Retries RegSetValueEx() MAX_ATTEMPTS times before giving up.

Methods inherited from class java.util.prefs.AbstractPreferences

absolutePath, addNodeChangeListener, addPreferenceChangeListener, cachedChildren, childrenNames, clear, exportNode, exportSubtree, get, getBoolean, getByteArray, getChild, getDouble, getFloat, getInt, getLong, isRemoved, isUserNode, keys, name, node, nodeExists, nodeListeners, parent, prefListeners, put, putBoolean, putByteArray, putDouble, putFloat, putInt, putLong, remove, removeNode, removeNodeChangeListener, removePreferenceChangeListener, toString

Methods inherited from class java.util.prefs.Preferences

importPreferences, systemNodeForPackage, systemRoot, userNodeForPackage, userRoot

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

logger

private static Logger logger

Logger for error messages

WINDOWS_ROOT_PATH

private static final byte[] WINDOWS_ROOT_PATH

Windows registry path to Preferences's root nodes.

HKEY_CURRENT_USER

private static final int HKEY_CURRENT_USER

Windows handles to HKEY_CURRENT_USER and HKEY_LOCAL_MACHINE hives.

See Also:

Constant Field Values

HKEY_LOCAL_MACHINE

private static final int HKEY_LOCAL_MACHINE

See Also:

Constant Field Values

USER_ROOT_NATIVE_HANDLE

private static final int USER_ROOT_NATIVE_HANDLE

Mount point for Preferences' user root.

See Also:

Constant Field Values

SYSTEM_ROOT_NATIVE_HANDLE

private static final int SYSTEM_ROOT_NATIVE_HANDLE

Mount point for Preferences' system root.

See Also:

Constant Field Values

MAX_WINDOWS_PATH_LENGTH

private static final int MAX_WINDOWS_PATH_LENGTH

Maximum byte-encoded path length for Windows native functions, ending null character not included.

See Also:

Constant Field Values

userRoot

static final Preferences userRoot

User root node.

systemRoot

static final Preferences systemRoot

System root node.

ERROR_SUCCESS

private static final int ERROR_SUCCESS

See Also:

Constant Field Values

ERROR_FILE_NOT_FOUND

private static final int ERROR_FILE_NOT_FOUND

See Also:

Constant Field Values

ERROR_ACCESS_DENIED

private static final int ERROR_ACCESS_DENIED

See Also:

Constant Field Values

NATIVE_HANDLE

private static final int NATIVE_HANDLE

See Also:

Constant Field Values

ERROR_CODE

private static final int ERROR_CODE

See Also:

Constant Field Values

SUBKEYS_NUMBER

private static final int SUBKEYS_NUMBER

See Also:

Constant Field Values

VALUES_NUMBER

private static final int VALUES_NUMBER

See Also:

Constant Field Values

MAX_KEY_LENGTH

private static final int MAX_KEY_LENGTH

See Also:

Constant Field Values

MAX_VALUE_NAME_LENGTH

private static final int MAX_VALUE_NAME_LENGTH

See Also:

Constant Field Values

DISPOSITION

private static final int DISPOSITION

See Also:

Constant Field Values

REG_CREATED_NEW_KEY

private static final int REG_CREATED_NEW_KEY

See Also:

Constant Field Values

REG_OPENED_EXISTING_KEY

private static final int REG_OPENED_EXISTING_KEY

See Also:

Constant Field Values

NULL_NATIVE_HANDLE

private static final int NULL_NATIVE_HANDLE

See Also:

Constant Field Values

DELETE

private static final int DELETE

See Also:

Constant Field Values

KEY_QUERY_VALUE

private static final int KEY_QUERY_VALUE

See Also:

Constant Field Values

KEY_SET_VALUE

private static final int KEY_SET_VALUE

See Also:

Constant Field Values

KEY_CREATE_SUB_KEY

private static final int KEY_CREATE_SUB_KEY

See Also:

Constant Field Values

KEY_ENUMERATE_SUB_KEYS

private static final int KEY_ENUMERATE_SUB_KEYS

See Also:

Constant Field Values

KEY_READ

private static final int KEY_READ

See Also:

Constant Field Values

KEY_WRITE

private static final int KEY_WRITE

See Also:

Constant Field Values

KEY_ALL_ACCESS

private static final int KEY_ALL_ACCESS

See Also:

Constant Field Values

INIT_SLEEP_TIME

private static int INIT_SLEEP_TIME

Initial time between registry access attempts, in ms. The time is doubled after each failing attempt (except the first).

MAX_ATTEMPTS

private static int MAX_ATTEMPTS

Maximum number of registry access attempts.

isBackingStoreAvailable

private boolean isBackingStoreAvailable

BackingStore availability flag.

Constructor Detail

WindowsPreferences

private WindowsPreferences(WindowsPreferences parent,
                           String name)

Constructs a WindowsPreferences node, creating underlying Windows registry node and all its Windows parents, if they are not yet created. Logs a warning message, if Windows Registry is unavailable.

WindowsPreferences

private WindowsPreferences(int rootNativeHandle,
                           byte[] rootDirectory)

Constructs a root node creating the underlying Windows registry node and all of its parents, if they have not yet been created. Logs a warning message, if Windows Registry is unavailable.

Parameters:

rootNativeHandle - Native handle to one of Windows top level keys.

rootDirectory - Path to root directory, as a byte-encoded string.

Method Detail

WindowsRegOpenKey

private static int[] WindowsRegOpenKey(int hKey,
                                       byte[] subKey,
                                       int securityMask)

Java wrapper for Windows registry API RegOpenKey()

WindowsRegOpenKey1

private static int[] WindowsRegOpenKey1(int hKey,
                                        byte[] subKey,
                                        int securityMask)

Retries RegOpenKey() MAX_ATTEMPTS times before giving up.

WindowsRegCloseKey

private static int WindowsRegCloseKey(int hKey)

Java wrapper for Windows registry API RegCloseKey()

WindowsRegCreateKeyEx

private static int[] WindowsRegCreateKeyEx(int hKey,
                                           byte[] subKey)

Java wrapper for Windows registry API RegCreateKeyEx()

WindowsRegCreateKeyEx1

private static int[] WindowsRegCreateKeyEx1(int hKey,
                                            byte[] subKey)

Retries RegCreateKeyEx() MAX_ATTEMPTS times before giving up.

WindowsRegDeleteKey

private static int WindowsRegDeleteKey(int hKey,
                                       byte[] subKey)

Java wrapper for Windows registry API RegDeleteKey()

WindowsRegFlushKey

private static int WindowsRegFlushKey(int hKey)

Java wrapper for Windows registry API RegFlushKey()

WindowsRegFlushKey1

private static int WindowsRegFlushKey1(int hKey)

Retries RegFlushKey() MAX_ATTEMPTS times before giving up.

WindowsRegQueryValueEx

private static byte[] WindowsRegQueryValueEx(int hKey,
                                             byte[] valueName)

Java wrapper for Windows registry API RegQueryValueEx()

WindowsRegSetValueEx

private static int WindowsRegSetValueEx(int hKey,
                                        byte[] valueName,
                                        byte[] value)

Java wrapper for Windows registry API RegSetValueEx()

WindowsRegSetValueEx1

private static int WindowsRegSetValueEx1(int hKey,
                                         byte[] valueName,
                                         byte[] value)

Retries RegSetValueEx() MAX_ATTEMPTS times before giving up.

WindowsRegDeleteValue

private static int WindowsRegDeleteValue(int hKey,
                                         byte[] valueName)

Java wrapper for Windows registry API RegDeleteValue()

WindowsRegQueryInfoKey

private static int[] WindowsRegQueryInfoKey(int hKey)

Java wrapper for Windows registry API RegQueryInfoKey()

WindowsRegQueryInfoKey1

private static int[] WindowsRegQueryInfoKey1(int hKey)

Retries RegQueryInfoKey() MAX_ATTEMPTS times before giving up.

WindowsRegEnumKeyEx

private static byte[] WindowsRegEnumKeyEx(int hKey,
                                          int subKeyIndex,
                                          int maxKeyLength)

Java wrapper for Windows registry API RegEnumKeyEx()

WindowsRegEnumKeyEx1

private static byte[] WindowsRegEnumKeyEx1(int hKey,
                                           int subKeyIndex,
                                           int maxKeyLength)

Retries RegEnumKeyEx() MAX_ATTEMPTS times before giving up.

WindowsRegEnumValue

private static byte[] WindowsRegEnumValue(int hKey,
                                          int valueIndex,
                                          int maxValueNameLength)

Java wrapper for Windows registry API RegEnumValue()

WindowsRegEnumValue1

private static byte[] WindowsRegEnumValue1(int hKey,
                                           int valueIndex,
                                           int maxValueNameLength)

Retries RegEnumValueEx() MAX_ATTEMPTS times before giving up.

windowsAbsolutePath

private byte[] windowsAbsolutePath()

Returns Windows absolute path of the current node as a byte array. Java "/" separator is transformed into Windows "\".

See Also:

Preferences.absolutePath()

openKey

private int openKey(int securityMask)

Opens current node's underlying Windows registry key using a given security mask.

Parameters:

securityMask - Windows security mask.

Returns:

Windows registry key's handle.

See Also:

#openKey(byte[], int), #openKey(int, byte[], int), closeKey(int)

openKey

private int openKey(int mask1,
                    int mask2)

Opens current node's underlying Windows registry key using a given security mask.

Parameters:

mask1 - Preferred Windows security mask.

mask2 - Alternate Windows security mask.

Returns:

Windows registry key's handle.

See Also:

#openKey(byte[], int), #openKey(int, byte[], int), closeKey(int)

openKey

private int openKey(byte[] windowsAbsolutePath,
                    int mask1,
                    int mask2)

Opens Windows registry key at a given absolute path using a given security mask.

Parameters:

windowsAbsolutePath - Windows absolute path of the key as a byte-encoded string.

mask1 - Preferred Windows security mask.

mask2 - Alternate Windows security mask.

Returns:

Windows registry key's handle.

See Also:

openKey(int), #openKey(int, byte[],int), closeKey(int)

openKey

private int openKey(int nativeHandle,
                    byte[] windowsRelativePath,
                    int mask1,
                    int mask2)

Opens Windows registry key at a given relative path with respect to a given Windows registry key.

Parameters:

nativeHandle - handle to the base Windows key.

mask1 - Preferred Windows security mask.

mask2 - Alternate Windows security mask.

Returns:

Windows registry key's handle.

See Also:

openKey(int), #openKey(byte[],int), closeKey(int)

closeKey

private void closeKey(int nativeHandle)

Closes Windows registry key. Logs a warning if Windows registry is unavailable.

See Also:

openKey(int), #openKey(byte[],int), #openKey(int, byte[],int)

putSpi

protected void putSpi(String javaName,
                      String value)

Implements AbstractPreferences putSpi() method. Puts name-value pair into the underlying Windows registry node. Logs a warning, if Windows registry is unavailable.

Specified by:

putSpi in class AbstractPreferences

See Also:

getSpi(String)

getSpi

protected String getSpi(String javaName)

Implements AbstractPreferences getSpi() method. Gets a string value from the underlying Windows registry node. Logs a warning, if Windows registry is unavailable.

Specified by:

getSpi in class AbstractPreferences

Returns:

the value associated with the specified key at this preference node, or null if there is no association for this key, or the association cannot be determined at this time.

See Also:

putSpi(String, String)

removeSpi

protected void removeSpi(String key)

Implements AbstractPreferences removeSpi() method. Deletes a string name-value pair from the underlying Windows registry node, if this value still exists. Logs a warning, if Windows registry is unavailable or key has already been deleted.

Specified by:

removeSpi in class AbstractPreferences

keysSpi

protected String[] keysSpi()
                    throws BackingStoreException

Implements AbstractPreferences keysSpi() method. Gets value names from the underlying Windows registry node. Throws a BackingStoreException and logs a warning, if Windows registry is unavailable.

Specified by:

keysSpi in class AbstractPreferences

Returns:

an array of the keys that have an associated value in this preference node.

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

childrenNamesSpi

protected String[] childrenNamesSpi()
                             throws BackingStoreException

Implements AbstractPreferences childrenNamesSpi() method. Calls Windows registry to retrive children of this node. Throws a BackingStoreException and logs a warning message, if Windows registry is not available.

Specified by:

childrenNamesSpi in class AbstractPreferences

Returns:

an array containing the names of the children of this preference node.

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

flush

public void flush()
           throws BackingStoreException

Implements Preferences flush() method. Flushes Windows registry changes to disk. Throws a BackingStoreException and logs a warning message if Windows registry is not available.

Overrides:

flush in class AbstractPreferences

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

See Also:

AbstractPreferences.flush()

sync

public void sync()
          throws BackingStoreException

Implements Preferences sync() method. Flushes Windows registry changes to disk. Equivalent to flush().

Overrides:

sync in class AbstractPreferences

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

See Also:

flush()

childSpi

protected AbstractPreferences childSpi(String name)

Implements AbstractPreferences childSpi() method. Constructs a child node with a given name and creates its underlying Windows registry node, if it does not exist. Logs a warning message, if Windows Registry is unavailable.

Specified by:

childSpi in class AbstractPreferences

Parameters:

name - The name of the child node to return, relative to this preference node.

Returns:

The named child node.

removeNodeSpi

public void removeNodeSpi()
                   throws BackingStoreException

Implements AbstractPreferences removeNodeSpi() method. Deletes underlying Windows registry node. Throws a BackingStoreException and logs a warning, if Windows registry is not available.

Specified by:

removeNodeSpi in class AbstractPreferences

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

toJavaName

private static String toJavaName(byte[] windowsNameArray)

Converts value's or node's name from its byte array representation to java string. Two encodings, simple and altBase64 are used. See toWindowsName() for a detailed description of encoding conventions.

Parameters:

windowsNameArray - Null-terminated byte array.

toJavaAlt64Name

private static String toJavaAlt64Name(String windowsName)

Converts value's or node's name from its Windows representation to java string, using altBase64 encoding. See toWindowsName() for a detailed description of encoding conventions.

toWindowsName

private static byte[] toWindowsName(String javaName)

Converts value's or node's name to its Windows representation as a byte-encoded string. Two encodings, simple and altBase64 are used.

Simple encoding is used, if java string does not contain any characters less, than 0x0020, or greater, than 0x007f. Simple encoding adds "/" character to capital letters, i.e. "A" is encoded as "/A". Character '\' is encoded as '//', '/' is encoded as '\'. The constructed string is converted to byte array by truncating the highest byte and adding the terminating null character.

altBase64 encoding is used, if java string does contain at least one character less, than 0x0020, or greater, than 0x007f. This encoding is marked by setting first two bytes of the Windows string to '/!'. The java name is then encoded using byteArrayToAltBase64() method from Base64 class.

toWindowsAlt64Name

private static byte[] toWindowsAlt64Name(String javaName)

Converts value's or node's name to its Windows representation as a byte-encoded string, using altBase64 encoding. See toWindowsName() for a detailed description of encoding conventions.

toJavaValueString

private static String toJavaValueString(byte[] windowsNameArray)

Converts value string from its Windows representation to java string. See toWindowsValueString() for the description of the encoding algorithm.

toWindowsValueString

private static byte[] toWindowsValueString(String javaName)

Converts value string to it Windows representation. as a byte-encoded string. Encoding algorithm adds "/" character to capital letters, i.e. "A" is encoded as "/A". Character '\' is encoded as '//', '/' is encoded as '\'. Then encoding scheme similar to jdk's native2ascii converter is used to convert java string to a byte array of ASCII characters.

rootNativeHandle

private int rootNativeHandle()

Returns native handle for the top Windows node for this node.

stringToByteArray

private static byte[] stringToByteArray(String str)

Returns this java string as a null-terminated byte array

byteArrayToString

private static String byteArrayToString(byte[] array)

Converts a null-terminated byte array to java string

flushSpi

protected void flushSpi()
                 throws BackingStoreException

Empty, never used implementation of AbstractPreferences.flushSpi().

Specified by:

flushSpi in class AbstractPreferences

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

syncSpi

protected void syncSpi()
                throws BackingStoreException

Empty, never used implementation of AbstractPreferences.flushSpi().

Specified by:

syncSpi in class AbstractPreferences

Throws:

BackingStoreException - if this operation cannot be completed due to a failure in the backing store, or inability to communicate with it.

logger

private static Logger logger()