Java Concurrent Programs in Oracle

Why the need for java concurrent program when we can write pl/sql concurrent programs? Let’s admit PL/SQL is primarily an Oracle database language. What if you wish to do the following seamlessly in a single pl/sql concurrent program:- Scenario 1.  FTP the file from a server securely, validate and load into apps using an API Scenario 2.  Connect to a non-oracle database using JDBC, fetch the data, load into Apps Custom tables, validate/transform and interface using API.