I notice the Eclipse has a very handy feature of double click: it can select text block, or select contents between surrounding quotes, So is there a shortcut available to do ju
Regarding the next TODO/FIXME position, there are 2 buttons in the toolbar - 'Previous Annotation' (the icon has an up arrow) and 'Next Annotation' (the icon has a down arrow) - which allow you to move from one annotation to another. Annotations are the markers in the editor - errors, warnings, breakpoints, TODOs etc. You can configure which annotations should the buttons traverse through by clicking on the dropdown (inverted triangle) icon next to the toolbar buttons.
Keyboard shortcut for 'Next Annotation' is 'Ctrl+.', these are also shown if you hover over the toolbar buttons.
PS: You might also find it useful to glance through the JDT tips and tricks document. The above mentioned toolbar buttons are also described in the document.