derby.system.home The derby.system.home property specifies the system directory, which is the directory that contains subdirectories holding databases that you create and the text file derby.properties. derby.system.home property system directoryspecifying

If the system directory that you specify with derby.system.home does not exist at startup, creates the directory automatically.

Default

Current directory (the value of the JVM system property user.dir).

If you do not explicitly set the derby.system.home property when starting , the default is the directory in which was started.

You should always explicitly set the value of derby.system.home.
Example -Dderby.system.home=C:\
Dynamic or static

This property is static; if you change it while is running, the change does not take effect until you reboot.