Alternative Linux development environments

HBasic
HBasic is an integrated development environment used to create, execute and debug programs with an BASIC style language. HBasic has object oriented features either in combination with precompiled C++ components (shared libraries) or class definitions (HBasic sourcecode). This also includes a version of inheritance. HBasic runs on Linux and uses the KDE GUI libraries.

Dabo Desktop Application Framework
Dabo is a 3-tier, cross-platform application development framework, written in Python atop the wxPython GUI toolkit. And while Dabo is designed to create database-centric apps, that is not a requirement. Lots of people are using Dabo for the GUI tools to create apps that have no need to connect to a database at all.

Lazarus
Lazarus is the class libraries for Free Pascal that emulate Delphi. Free Pascal is a GPL'ed compiler that runs on Linux, Win32, OS/2, 68K and more. Free Pascal is designed to be able to understand and compile Delphi syntax, which is of course OOP. Lazarus is the part of the missing puzzle that will allow you to develop Delphi like programs in all of the above platforms. Unlike Java which strives to be a write once run anywhere, Lazarus and Free Pascal strives for write once compile anywhere. Since the exact same compiler is available on all of the above platforms it means you don't need to do any recoding to produce identical products for different platforms.

Hat tip: Linux Action Show