H2 Database
H2 is a Java-based Database which replaced Derby as the default database in Payara 5. Derby as a database service that can be started and managed by Payara Server Community, has been removed starting from version 5.201
Why replace Derby?
In terms of performance, Derby is one of the slowest embedded databases as compared to other H2, PostgresSQL, HSQLDB, etc. H2 also has a smaller disk footprint; the size of a JAR file is around 1.5 MB.