Ubuntu .desktop file

.desktop

[Desktop Entry]
Type=Application
Name=EclipseC++
GenericName=Eclipse
Comment=Eclipse for development
Exec=/path/to/eclipse
Icon=/path/to/icon.xpm
Terminal=false
MimeType=text/plain;
Categories=Development;IDE
StartupNotify=true

# If you won't specify following line you may end having duplicate icons
# in Ubuntu Dock bar where first is the one you have added to Dock and the 
# other one is showing the running application. To avoid this issue you need
# to add following line in .desktop file
StartupWMClass=Eclipse

# How to determine value of StartWMClass for any application:
# - Run your application
# - Run xprop WM_CLASS from the commandline
# - Your mouse cursor will be in different shape
# - Click the window bar of the your application
# - Note down the value(s) printed on the console where you executed xprop
# - These printed values will be WM_CLASS(STRING) = "ABC", "RST", "XYZ" 
# - Use any of the string shown in "xxx" for StartupWMClass in .desktop file. For example
#   you can use ABC or RST or XYZ.

.desktop (simple)

[Desktop Entry]
Version=1.0
Type=Application
Terminal=false
Exec=/path/to/executable
Name=Hell world
Icon=/path/to/icon