[mykolas@sr1220 ~]$ java -version java version "1.6.0" OpenJDK Runtime Environment (build 1.6.0-b09) OpenJDK Client VM (build 1.6.0-b09, mixed mode)
So, you have Java installed
Sweet Home 3D - a CAD-style house layout program. http://sweethome3d.eu/index.jsp
Just download it from: http://prdownloads.sourceforge.net/sweethome3d/SweetHome3D-2.3-linux-x86.tgz
Untar it and click on the SweetHome3D script and it will start it (I just tried) They actually ship it with a JVM.
Note: If you want to use their online offer, then you need the Java browser plugin because they use applets, in that case follow the instructions for the Sun JDK..