RPG
RPG, which stands for Report Program Generator, is a easy to learn and understand programming language that is well suited for developing business applications.
There are four major versions of RPG currently in use... RPG II, RPG III, RPG 400, and RPG 4 (sometimes referred to as ILE RPG).
The RPG400-L mailing list hosted by midrange.com is for discussion of RPG programming.
RPG is only available only on IBM Midrange platforms, this is because the technology has evolved over many years to leverage operating system resources. A comparison between RPG and Java can be made so long as Java is used in a developer framework or one of the available application servers. Unlike Java, however RPG contains language-level features for common business tasks such as database access. Also the operating system contains extensive support for debugging and run-time identification of RPG code. The main perceived flaw with RPG is that it is not object oriented, nor does it contain direct support for GUI Graphical User Interface. There is a large established base of RPG code in production environments, usually performing heavy-lifting batch-oriented data tasks, or providing support for interactive ERP applications, either with native 5250 interface or with a GUI or Web Skin applied over the 5250 data stream.