How to add Eclipse to Favorites?

I merged this answer, OP's answer, below comments and my own experience:

  1. Create a file called Eclipse.desktop in ~/.local/share/applications (e.g. with the command nano ~/.local/share/applications/Eclipse.desktop)

  2. Add these lines:

    [Desktop Entry]
    Comment=Eclipse
    Terminal=false
    Name=Eclipse
    Exec=/path/to/your/version/eclipse/eclipse
    Type=Application
    Icon=/path/to/your/version/eclipse/icon.xpm
    StartupWMClass=Eclipse
    

    Note that 'Exec' should point to your eclipse executable, not the containing folder which is also named 'eclipse' usually. Check if the icon file is present and if necessary adapt its path. Save the file.

  3. Make the file executable by running chmod a+x ~/.local/share/applications/Eclipse.desktop.

  4. Click on 'Show Applications' (the dot logo on the bottom left of the screen) and in the search bar enter 'Eclipse'. It should appear.

  5. Right click on the Icon and choose 'Add to favorites'.

There is a lot more you can specify in a .desktop file with further key-value pairs, more info here.