# After installing

This section provides reference information about the installation directory, JVMs, classpath, upgrades, and platform-specific issues.

Review the `index.html` file at the top level of the Derby distribution for pointers to reference and tutorial information about Derby. See the Release Notes for information on platform support, changes that may affect your existing applications, defect information, and recent documentation updates. See Getting Started with Derby for basic product descriptions, information on getting started, and directions for setting the path and the classpath/modulepath.

- The installation directory
  You may install the Derby software in a directory of your choice.
- Derby and Java Virtual Machines (JVMs)
  Derby is a database engine written completely in the Java programming language; it will run in any JVM that is version 19 or higher.
- Derby libraries and classpath/modulepath
  Derby libraries are located in the /lib subdirectory of the Derby base directory. You must set the classpath/modulepath on your development machine to include the appropriate libraries.
- UNIX-specific issues
  This section discusses Derby issues specifically related to UNIX platforms.