What does CTRL-G do in Eclipse?
CTRL+G
Find **declarations** in workspace
CTRL+Shift+G
Find **references** in workspace
If you want to change those,open Windows->Preferences->General->Keys.
Now you can use the filter to find your shortcut and change its binding.
To find out in general what any keyboard shortcut does in Eclipse, go to Preferences | Keys. Type the combination in the Binding text box and you'll see its current binding.