I\'m looking for embedded db with Java API for testing purposes. Also i need pl/sql support because we use oracle in production and migrations are written in pl/sql.
We use Firebird's pl/sql extensively. It has an embedded server you can access through JDBC.
You could try installing Oracle XE on your local developer workstation and Continuous Integration server. Then connect with the SYS as SYSDBA or SYSTEM user to create your schema(s) before executing your unit tests.
According to the wikipedia page about PL/SQL, the databases supporting PL/SQL are Oracle and DB2:
If these don't suit you, there's nothing else. PL/SQL is a creation of Oracle, so it's not expected to be widely spread.