ASA Programming Guide
  Using Java in the Database
    Special features of Java classes in the database

Using threads in Java applications

With features of the java.lang.Thread package, you can use multiple threads in a Java application. Each Java thread is an engine thread, and comes from the number of threads permitted by the -gn database server option.

You can synchronize, suspend, resume, interrupt, or stop threads in Java applications.

For more information about database server threads, see -gn server option.

Serialization of JDBC calls 

All calls to the server-side JDBC driver are serialized, such that only one thread is actively executing JDBC at any one time.