HSQLDB

HSQLDB (HyperSQL DataBase) is an open-source, lightweight database system written in Java. It allows applications to store, retrieve, and manage data efficiently without requiring complex setup or heavy resources. Often used in development, testing, and small to medium-sized applications, HSQLDB can run right within a program or as a standalone server. Its ease of use, fast performance, and compatibility with SQL (Structured Query Language) make it a popular choice for developers needing a reliable, embedded database solution.