An Apache Derby database contains dictionary objects such as tables, columns, indexes, and .JAR files. An Apache Derby database can also store its own configuration information.
An Apache Derby database is stored in files that live in a directory with the same name as the database (that is, the SAMPLE database is found in the SAMPLE directory). Database directories typically live in system directories. A database directory contains the following objects:
log directory— This directory contains files that make up the database transaction log, used internally for data recovery.
seg0 directory— This directory contains one file for each user table, system table, and index.
service.properties file— This is a text file with internal ...