A transaction is a set of one or more SQL statements that make up a logical unit of work that you can either commit or roll back and that will be recovered in the event of a system failure. All the statements in the transaction are atomic. A transaction is associated with a single Connection object (and database). A transaction cannot span Connections (or databases).
Derby permits schema and data manipulation statements (DML) to be intermixed within a single transaction. If you create a table in one transaction, you can also insert into it in that same transaction. A schema manipulation statement (DDL) is not automatically committed when it is performed, but participates in the transaction within which it is issued. Because DDL requires exclusive locks on system tables, keep transactions that involve DDL short.