Title more or less says it all. Specifically, I\'ve become increasingly annoyed that in order to run an ant script I have to use Alt+Shift+x
Window > Preferences > General > Keys
In particular, edit the "Run Ant Build" command.
For mac that would be
Eclipse > Preferences > General > Keys
For Windows:
Window > Preferences > General > Keys
As a side note make sure your newly mapped Shortcut won't have any conflicts on the right of the Keys window/menu.
If so choose a combination that will work; doesn't have any conflicts with existing ( default ) settings.
Hope this helps.
Pressing Ctrl + Shift + L will open the current list of defined shortcuts, again pressing Ctrl + Shift + L will open preference page from where the shortcuts can be modified.