Common problems and updates on Eclipse

Common problems (and solutions if solved) and updates related to Eclipse installation and usage based on personal experience.

Environment : Linux Fedora 14. Java version "1.6.0_20".
OpenJDK Runtime Environment (IcedTea6 1.9.5)  (fedora-51.1.9.5.fc14-i386). OpenJDK Client VM (build 19.0-b09, mixed mode).
If not mentioned Eclipse Helios 3.6.1 instance is used, downloaded and installed from Fedora's default package (Add/Remove Software).

Python from zero

Personal log in learning python.
Environment : Linux Fedora 14, Python 2.7