SQLiteDatabase

CONFLICT_ABORT

int CONFLICT_ABORT

When a constraint violation occurs,no ROLLBACK is executed so changes from prior commands within the same transaction are preserved. This is the default behavior.

Constant Value: 2 (0x00000002)

CONFLICT_FAIL

int CONFLICT_FAIL

When a constraint violation occurs, the command aborts with a return code SQLITE_CONSTRAINT. But any changes to the database that the command made prior to encountering the constraint violation are preserved and are not backed out.

Constant Value: 3 (0x00000003)

CONFLICT_IGNORE

int CONFLICT_IGNORE

When a constraint violation occurs, the one row that contains the constraint violation is not inserted or changed. But the command continues executing normally. Other rows before and after the row that contained the constraint violation continue to be inserted or updated normally. No error is returned.

Constant Value: 4 (0x00000004)

CONFLICT_NONE

int CONFLICT_NONE

Use the following when no conflict action is specified.

Constant Value: 0 (0x00000000)

CONFLICT_REPLACE

int CONFLICT_REPLACE

When a UNIQUE constraint violation occurs, the pre-existing rows that are causing the constraint violation are removed prior to inserting or updating the current row. Thus the insert or update always occurs. The command continues executing normally. No error is returned. If a NOT NULL constraint violation occurs, the NULL value is replaced by the default value for that column. If the column has no default value, then the ABORT algorithm is used. If a CHECK constraint violation occurs then the IGNORE algorithm is used. When this conflict resolution strategy deletes rows in order to satisfy a constraint, it does not invoke delete triggers on those rows. This behavior might change in a future release.

Constant Value: 5 (0x00000005)

CONFLICT_ROLLBACK

int CONFLICT_ROLLBACK

When a constraint violation occurs, an immediate ROLLBACK occurs, thus ending the current transaction, and the command aborts with a return code of SQLITE_CONSTRAINT. If no transaction is active (other than the implied transaction that is created on every command) then this algorithm works the same as ABORT.

Constant Value: 1 (0x00000001)

CREATE_IF_NECESSARY

int CREATE_IF_NECESSARY

Open flag: Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to create the database file if it does not already exist.

Constant Value: 268435456 (0x10000000)

ENABLE_WRITE_AHEAD_LOGGING

int ENABLE_WRITE_AHEAD_LOGGING

Open flag: Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database file with write-ahead logging enabled by default. Using this flag is more efficient than calling enableWriteAheadLogging(). Write-ahead logging cannot be used with read-only databases so the value of this flag is ignored if the database is opened read-only.

Constant Value: 536870912 (0x20000000)

MAX_SQL_CACHE_SIZE

int MAX_SQL_CACHE_SIZE

Absolute max value that can be set by setMaxSqlCacheSize(int). Each prepared-statement is between 1K - 6K, depending on the complexity of the SQL statement & schema. A large SQL cache may use a significant amount of memory.

Constant Value: 100 (0x00000064)

NO_LOCALIZED_COLLATORS

int NO_LOCALIZED_COLLATORS

Open flag: Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database without support for localized collators.

This causes the collator LOCALIZED not to be created. You must be consistent when using this flag to use the setting the database was created with. If this is set, setLocale(Locale) will do nothing.

Constant Value: 16 (0x00000010)

OPEN_READONLY

int OPEN_READONLY

Open flag: Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database for reading only. This is the only reliable way to open a database if the disk may be full.

Constant Value: 1 (0x00000001)

OPEN_READWRITE

int OPEN_READWRITE

Open flag: Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database for reading and writing. If the disk is full, this may fail even before you actually write anything.

Note that the value of this flag is 0, so it is the default.

Constant Value: 0 (0x00000000)

SQLITE_MAX_LIKE_PATTERN_LENGTH

int SQLITE_MAX_LIKE_PATTERN_LENGTH

Maximum Length Of A LIKE Or GLOB Pattern The pattern matching algorithm used in the default LIKE and GLOB implementation of SQLite can exhibit O(N^2) performance (where N is the number of characters in the pattern) for certain pathological cases. To avoid denial-of-service attacks the length of the LIKE or GLOB pattern is limited to SQLITE_MAX_LIKE_PATTERN_LENGTH bytes. The default value of this limit is 50000. A modern workstation can evaluate even a pathological LIKE or GLOB pattern of 50000 bytes relatively quickly. The denial of service problem only comes into play when the pattern length gets into millions of bytes. Nevertheless, since most useful LIKE or GLOB patterns are at most a few dozen bytes in length, paranoid application developers may want to reduce this parameter to something in the range of a few hundred if they know that external users are able to generate arbitrary patterns.

Constant Value: 50000 (0x0000c350)

beginTransaction

void beginTransaction ()

Begins a transaction in EXCLUSIVE mode.

Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

   db.beginTransaction();
   try {
     ...
     db.setTransactionSuccessful();
   } finally {
     db.endTransaction();
   }
 

beginTransactionNonExclusive

void beginTransactionNonExclusive ()

Begins a transaction in IMMEDIATE mode. Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

   db.beginTransactionNonExclusive();
   try {
     ...
     db.setTransactionSuccessful();
   } finally {
     db.endTransaction();
   }
 

beginTransactionWithListener

void beginTransactionWithListener (SQLiteTransactionListener transactionListener)

Begins a transaction in EXCLUSIVE mode.

Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

   db.beginTransactionWithListener(listener);
   try {
     ...
     db.setTransactionSuccessful();
   } finally {
     db.endTransaction();
   }
 

beginTransactionWithListenerNonExclusive

void beginTransactionWithListenerNonExclusive (SQLiteTransactionListener transactionListener)

Begins a transaction in IMMEDIATE mode. Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

   db.beginTransactionWithListenerNonExclusive(listener);
   try {
     ...
     db.setTransactionSuccessful();
   } finally {
     db.endTransaction();
   }
 

compileStatement

SQLiteStatement compileStatement (String sql)

Compiles an SQL statement into a reusable pre-compiled statement object. The parameters are identical to execSQL(String). You may put ?s in the statement and fill in those values with bindString(int, String) and bindLong(int, long) each time you want to run the statement. Statements may not return result sets larger than 1x1.

No two threads should be using the same SQLiteStatement at the same time.

create

SQLiteDatabase create (SQLiteDatabase.CursorFactory factory)

Create a memory backed SQLite database. Its contents will be destroyed when the database is closed.

Sets the locale of the database to the the system's current locale. Call setLocale(Locale) if you would like something else.

delete

int delete (String table, 
                String whereClause, 
                String[] whereArgs)

Convenience method for deleting rows in the database.

deleteDatabase

boolean deleteDatabase (File file)

Deletes a database including its journal file and other auxiliary files that may have been created by the database engine.

disableWriteAheadLogging

void disableWriteAheadLogging ()

This method disables the features enabled by enableWriteAheadLogging().

enableWriteAheadLogging

boolean enableWriteAheadLogging ()

This method enables parallel execution of queries from multiple threads on the same database. It does this by opening multiple connections to the database and using a different database connection for each query. The database journal mode is also changed to enable writes to proceed concurrently with reads.

When write-ahead logging is not enabled (the default), it is not possible for reads and writes to occur on the database at the same time. Before modifying the database, the writer implicitly acquires an exclusive lock on the database which prevents readers from accessing the database until the write is completed.

In contrast, when write-ahead logging is enabled (by calling this method), write operations occur in a separate log file which allows reads to proceed concurrently. While a write is in progress, readers on other threads will perceive the state of the database as it was before the write began. When the write completes, readers on other threads will then perceive the new state of the database.

It is a good idea to enable write-ahead logging whenever a database will be concurrently accessed and modified by multiple threads at the same time. However, write-ahead logging uses significantly more memory than ordinary journaling because there are multiple connections to the same database. So if a database will only be used by a single thread, or if optimizing concurrency is not very important, then write-ahead logging should be disabled.

After calling this method, execution of queries in parallel is enabled as long as the database remains open. To disable execution of queries in parallel, either call disableWriteAheadLogging() or close the database and reopen it.

The maximum number of connections used to execute queries in parallel is dependent upon the device memory and possibly other properties.

If a query is part of a transaction, then it is executed on the same database handle the transaction was begun.

Writers should use beginTransactionNonExclusive() or beginTransactionWithListenerNonExclusive(SQLiteTransactionListener) to start a transaction. Non-exclusive mode allows database file to be in readable by other threads executing queries.

If the database has any attached databases, then execution of queries in parallel is NOT possible. Likewise, write-ahead logging is not supported for read-only databases or memory databases. In such cases, enableWriteAheadLogging() returns false.

The best way to enable write-ahead logging is to pass the ENABLE_WRITE_AHEAD_LOGGING flag to openDatabase(String, SQLiteDatabase.CursorFactory, int). This is more efficient than calling enableWriteAheadLogging().

     SQLiteDatabase db = SQLiteDatabase.openDatabase("db_filename", cursorFactory,
             SQLiteDatabase.CREATE_IF_NECESSARY | SQLiteDatabase.ENABLE_WRITE_AHEAD_LOGGING,
             myDatabaseErrorHandler);
     db.enableWriteAheadLogging();
 

Another way to enable write-ahead logging is to call enableWriteAheadLogging() after opening the database.

     SQLiteDatabase db = SQLiteDatabase.openDatabase("db_filename", cursorFactory,
             SQLiteDatabase.CREATE_IF_NECESSARY, myDatabaseErrorHandler);
     db.enableWriteAheadLogging();
 

See also SQLite Write-Ahead Logging for more details about how write-ahead logging works.

endTransaction

void endTransaction ()

End a transaction. See beginTransaction for notes about how to use this and when transactions are committed and rolled back.

execSQL

void execSQL (String sql)

Execute a single SQL statement that is NOT a SELECT or any other SQL statement that returns data.

It has no means to return any data (such as the number of affected rows). Instead, you're encouraged to use insert(String, String, ContentValues), update(String, ContentValues, String, String[]), et al, when possible.

When using enableWriteAheadLogging(), journal_mode is automatically managed by this class. So, do not set journal_mode using "PRAGMA journal_mode'" statement if your app is using enableWriteAheadLogging()

execSQL

void execSQL (String sql, 
                Object[] bindArgs)

Execute a single SQL statement that is NOT a SELECT/INSERT/UPDATE/DELETE.

For INSERT statements, use any of the following instead.

• insert(String, String, ContentValues)
• insertOrThrow(String, String, ContentValues)
• insertWithOnConflict(String, String, ContentValues, int)

For UPDATE statements, use any of the following instead.

• update(String, ContentValues, String, String[])
• updateWithOnConflict(String, ContentValues, String, String[], int)

For DELETE statements, use any of the following instead.

• delete(String, String, String[])

For example, the following are good candidates for using this method:

• ALTER TABLE
• CREATE or DROP table / trigger / view / index / virtual table
• REINDEX
• RELEASE
• SAVEPOINT
• PRAGMA that returns no data

When using enableWriteAheadLogging(), journal_mode is automatically managed by this class. So, do not set journal_mode using "PRAGMA journal_mode'" statement if your app is using enableWriteAheadLogging()

findEditTable

String findEditTable (String tables)

Finds the name of the first table, which is editable.

getAttachedDbs

List<Pair<String, String>> getAttachedDbs ()

Returns list of full pathnames of all attached databases including the main database by executing 'pragma database_list' on the database.

getMaximumSize

long getMaximumSize ()

Returns the maximum size the database may grow to.

getPageSize

long getPageSize ()

Returns the current database page size, in bytes.

getPath

String getPath ()

Gets the path to the database file.

getSyncedTables

Map<String, String> getSyncedTables ()

This method was deprecated in API level 11.
This method no longer serves any useful purpose and has been deprecated.

Deprecated.

getVersion

int getVersion ()

Gets the database version.

inTransaction

boolean inTransaction ()

Returns true if the current thread has a transaction pending.

insert

long insert (String table, 
                String nullColumnHack, 
                ContentValues values)

Convenience method for inserting a row into the database.

insertOrThrow

long insertOrThrow (String table, 
                String nullColumnHack, 
                ContentValues values)

Convenience method for inserting a row into the database.

insertWithOnConflict

long insertWithOnConflict (String table, 
                String nullColumnHack, 
                ContentValues initialValues, 
                int conflictAlgorithm)

General method for inserting a row into the database.

isDatabaseIntegrityOk

boolean isDatabaseIntegrityOk ()

Runs 'pragma integrity_check' on the given database (and all the attached databases) and returns true if the given database (and all its attached databases) pass integrity_check, false otherwise.

If the result is false, then this method logs the errors reported by the integrity_check command execution.

Note that 'pragma integrity_check' on a database can take a long time.

isDbLockedByCurrentThread

boolean isDbLockedByCurrentThread ()

Returns true if the current thread is holding an active connection to the database.

The name of this method comes from a time when having an active connection to the database meant that the thread was holding an actual lock on the database. Nowadays, there is no longer a true "database lock" although threads may block if they cannot acquire a database connection to perform a particular operation.

isDbLockedByOtherThreads

boolean isDbLockedByOtherThreads ()

This method was deprecated in API level 16.
Always returns false. Do not use this method.

Always returns false.

There is no longer the concept of a database lock, so this method always returns false.

isOpen

boolean isOpen ()

Returns true if the database is currently open.

isReadOnly

boolean isReadOnly ()

Returns true if the database is opened as read only.

isWriteAheadLoggingEnabled

boolean isWriteAheadLoggingEnabled ()

Returns true if write-ahead logging has been enabled for this database.

markTableSyncable

void markTableSyncable (String table, 
                String deletedTable)

This method was deprecated in API level 11.
This method no longer serves any useful purpose and has been deprecated.

Mark this table as syncable. When an update occurs in this table the _sync_dirty field will be set to ensure proper syncing operation.

markTableSyncable

void markTableSyncable (String table, 
                String foreignKey, 
                String updateTable)

This method was deprecated in API level 11.
This method no longer serves any useful purpose and has been deprecated.

Mark this table as syncable, with the _sync_dirty residing in another table. When an update occurs in this table the _sync_dirty field of the row in updateTable with the _id in foreignKey will be set to ensure proper syncing operation.

needUpgrade

boolean needUpgrade (int newVersion)

Returns true if the new version code is greater than the current database version.

openDatabase

SQLiteDatabase openDatabase (String path, 
                SQLiteDatabase.CursorFactory factory, 
                int flags)

Open the database according to the flags OPEN_READWRITE OPEN_READONLY CREATE_IF_NECESSARY and/or NO_LOCALIZED_COLLATORS.

Sets the locale of the database to the the system's current locale. Call setLocale(Locale) if you would like something else.

openDatabase

SQLiteDatabase openDatabase (String path, 
                SQLiteDatabase.CursorFactory factory, 
                int flags, 
                DatabaseErrorHandler errorHandler)

Open the database according to the flags OPEN_READWRITE OPEN_READONLY CREATE_IF_NECESSARY and/or NO_LOCALIZED_COLLATORS.

Sets the locale of the database to the the system's current locale. Call setLocale(Locale) if you would like something else.

Accepts input param: a concrete instance of DatabaseErrorHandler to be used to handle corruption when sqlite reports database corruption.

openOrCreateDatabase

SQLiteDatabase openOrCreateDatabase (File file, 
                SQLiteDatabase.CursorFactory factory)

Equivalent to openDatabase(file.getPath(), factory, CREATE_IF_NECESSARY).

openOrCreateDatabase

SQLiteDatabase openOrCreateDatabase (String path, 
                SQLiteDatabase.CursorFactory factory, 
                DatabaseErrorHandler errorHandler)

Equivalent to openDatabase(path, factory, CREATE_IF_NECESSARY, errorHandler).

openOrCreateDatabase

SQLiteDatabase openOrCreateDatabase (String path, 
                SQLiteDatabase.CursorFactory factory)

Equivalent to openDatabase(path, factory, CREATE_IF_NECESSARY).

query

Cursor query (boolean distinct, 
                String table, 
                String[] columns, 
                String selection, 
                String[] selectionArgs, 
                String groupBy, 
                String having, 
                String orderBy, 
                String limit)

Query the given URL, returning a Cursor over the result set.

query

Cursor query (String table, 
                String[] columns, 
                String selection, 
                String[] selectionArgs, 
                String groupBy, 
                String having, 
                String orderBy, 
                String limit)

Query the given table, returning a Cursor over the result set.

query

Cursor query (boolean distinct, 
                String table, 
                String[] columns, 
                String selection, 
                String[] selectionArgs, 
                String groupBy, 
                String having, 
                String orderBy, 
                String limit, 
                CancellationSignal cancellationSignal)

Query the given URL, returning a Cursor over the result set.

query

Cursor query (String table, 
                String[] columns, 
                String selection, 
                String[] selectionArgs, 
                String groupBy, 
                String having, 
                String orderBy)

Query the given table, returning a Cursor over the result set.

queryWithFactory

Cursor queryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, 
                boolean distinct, 
                String table, 
                String[] columns, 
                String selection, 
                String[] selectionArgs, 
                String groupBy, 
                String having, 
                String orderBy, 
                String limit, 
                CancellationSignal cancellationSignal)

Query the given URL, returning a Cursor over the result set.

queryWithFactory

Cursor queryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, 
                boolean distinct, 
                String table, 
                String[] columns, 
                String selection, 
                String[] selectionArgs, 
                String groupBy, 
                String having, 
                String orderBy, 
                String limit)

Query the given URL, returning a Cursor over the result set.

rawQuery

Cursor rawQuery (String sql, 
                String[] selectionArgs, 
                CancellationSignal cancellationSignal)

Runs the provided SQL and returns a Cursor over the result set.

rawQuery

Cursor rawQuery (String sql, 
                String[] selectionArgs)

Runs the provided SQL and returns a Cursor over the result set.

rawQueryWithFactory

Cursor rawQueryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, 
                String sql, 
                String[] selectionArgs, 
                String editTable, 
                CancellationSignal cancellationSignal)

Runs the provided SQL and returns a cursor over the result set.

rawQueryWithFactory

Cursor rawQueryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, 
                String sql, 
                String[] selectionArgs, 
                String editTable)

Runs the provided SQL and returns a cursor over the result set.

releaseMemory

int releaseMemory ()

Attempts to release memory that SQLite holds but does not require to operate properly. Typically this memory will come from the page cache.

replace

long replace (String table, 
                String nullColumnHack, 
                ContentValues initialValues)

Convenience method for replacing a row in the database.

replaceOrThrow

long replaceOrThrow (String table, 
                String nullColumnHack, 
                ContentValues initialValues)

Convenience method for replacing a row in the database.

setForeignKeyConstraintsEnabled

void setForeignKeyConstraintsEnabled (boolean enable)

Sets whether foreign key constraints are enabled for the database.

By default, foreign key constraints are not enforced by the database. This method allows an application to enable foreign key constraints. It must be called each time the database is opened to ensure that foreign key constraints are enabled for the session.

A good time to call this method is right after calling openOrCreateDatabase(File, SQLiteDatabase.CursorFactory) or in the onConfigure(SQLiteDatabase) callback.

When foreign key constraints are disabled, the database does not check whether changes to the database will violate foreign key constraints. Likewise, when foreign key constraints are disabled, the database will not execute cascade delete or update triggers. As a result, it is possible for the database state to become inconsistent. To perform a database integrity check, call isDatabaseIntegrityOk().

This method must not be called while a transaction is in progress.

See also SQLite Foreign Key Constraints for more details about foreign key constraint support.

setLocale

void setLocale (Locale locale)

Sets the locale for this database. Does nothing if this database has the NO_LOCALIZED_COLLATORS flag set or was opened read only.

setLockingEnabled

void setLockingEnabled (boolean lockingEnabled)

This method was deprecated in API level 16.
This method now does nothing. Do not use.

Control whether or not the SQLiteDatabase is made thread-safe by using locks around critical sections. This is pretty expensive, so if you know that your DB will only be used by a single thread then you should set this to false. The default is true.

setMaxSqlCacheSize

void setMaxSqlCacheSize (int cacheSize)

Sets the maximum size of the prepared-statement cache for this database. (size of the cache = number of compiled-sql-statements stored in the cache).

Maximum cache size can ONLY be increased from its current size (default = 10). If this method is called with smaller size than the current maximum value, then IllegalStateException is thrown.

This method is thread-safe.

setMaximumSize

long setMaximumSize (long numBytes)

Sets the maximum size the database will grow to. The maximum size cannot be set below the current size.

setPageSize

void setPageSize (long numBytes)

Sets the database page size. The page size must be a power of two. This method does not work if any data has been written to the database file, and must be called right after the database has been created.

setTransactionSuccessful

void setTransactionSuccessful ()

Marks the current transaction as successful. Do not do any more database work between calling this and calling endTransaction. Do as little non-database work as possible in that situation too. If any errors are encountered between this and endTransaction the transaction will still be committed.

setVersion

void setVersion (int version)

Sets the database version.

toString

String toString ()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

update

int update (String table, 
                ContentValues values, 
                String whereClause, 
                String[] whereArgs)

Convenience method for updating rows in the database.

updateWithOnConflict

int updateWithOnConflict (String table, 
                ContentValues values, 
                String whereClause, 
                String[] whereArgs, 
                int conflictAlgorithm)

Convenience method for updating rows in the database.

validateSql

void validateSql (String sql, 
                CancellationSignal cancellationSignal)

Verifies that a SQL SELECT statement is valid by compiling it. If the SQL statement is not valid, this method will throw a SQLiteException.

yieldIfContended

boolean yieldIfContended ()

This method was deprecated in API level 3.
if the db is locked more than once (becuase of nested transactions) then the lock will not be yielded. Use yieldIfContendedSafely instead.

Temporarily end the transaction to let other threads run. The transaction is assumed to be successful so far. Do not call setTransactionSuccessful before calling this. When this returns a new transaction will have been created but not marked as successful.

yieldIfContendedSafely

boolean yieldIfContendedSafely ()

Temporarily end the transaction to let other threads run. The transaction is assumed to be successful so far. Do not call setTransactionSuccessful before calling this. When this returns a new transaction will have been created but not marked as successful. This assumes that there are no nested transactions (beginTransaction has only been called once) and will throw an exception if that is not the case.

yieldIfContendedSafely

boolean yieldIfContendedSafely (long sleepAfterYieldDelay)

Temporarily end the transaction to let other threads run. The transaction is assumed to be successful so far. Do not call setTransactionSuccessful before calling this. When this returns a new transaction will have been created but not marked as successful. This assumes that there are no nested transactions (beginTransaction has only been called once) and will throw an exception if that is not the case.

finalize

void finalize ()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java^TM virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

onAllReferencesReleased

void onAllReferencesReleased ()

Called when the last reference to the object was released by a call to releaseReference() or close().