Function
On some platforms, if set to true, prevents from booting a
database if a db.lck file is present in the database
directory.
attempts to prevent two JVMs from accessing a database at one
time (and potentially corrupting it) with the use of a file called db.lck in the database directory. On some operating systems, the use
of a lock file does not guarantee single access, and so only issues
a warning and might allow multiple JVM access even when the file is present.
(For more information, see "Double-Booting System Behavior" in Chapter
1 of the .)
provides the property derby.database.forceDatabaseLock for use on platforms that do not provide the ability for to
guarantee single JVM access. By default, this property is set to false. When
this property is set to true, if finds the db.lck file when it attempts to boot the database, it throws an exception
and does not boot the database.
This situation can occur
even when no other JVMs are accessing the database; in that case, remove the db.lck file by hand in order to boot the database. If
the db.lck file is removed by hand while a JVM is
still accessing a database, there is no way for to
prevent a second VM from starting up and possibly corrupting the database.
In this situation no warning message is logged to the error log.