How can I configure the font size for the tree item in the package explorer/outline in Eclipse?
Which item in Font under Preferences I should change?
Here is an option that works on my Windows7 machine suggested by Diego V: https://stackoverflow.com/a/15011440/1713920
On Juno you can adjust that font by CSS.
Lookup the files in eclipse\plugins\org.eclipse.platform_4.2.x.y\css for your current style sheet (probably e4_default_win7.css), and then just add the following rule:
#org-eclipse-jdt-ui-PackageExplorer Tree, #org-eclipse-ui-navigator-ProjectExplorer Tree { font-size: 10px; /* <-- Desired font size */ }