When using java, one might need to call up either a pl/sql procedure, functions or a package stored on the database. One way to do this is to use the standard JDBC (Java Database Connectivity) wrapper, but the Pl/SQL data complexity could make that operation difficult, as might be the case with a Pl/SQL object collection.
JPublisher is an Oracle utility that helps create a java wrapper that will represent database entities: User-defined SQL object types, Object reference types (REF types), User-defined SQL collection types (VARRAY types or nested table types), PL/SQL packages, SQL queries and DML statements. You can find more information about JPublisher here: link.