MacOSX: how to disable accented characters input

keyboard -> input source -> + -> other -> "Unicode Hex Input"

this will disable the option key for special characters.

I also removed all other input sources to avoid conflicts

If you are looking to disable auto accents for languages other than U.S. English, I made a workaround solution here: How to prevent the typing of special characters like "~" modifying the next keyboard input?

Yes! It's a shame that I didn't know about such a simple thing - but this is because I'm not a mac-maniac, I live on several OSes at once. When I've found out that quote + symbol gives me an accented character I've realized what's happening.

This was very easy:

• Launch System Preferences, open the Language & Text pane.
• Click the Input Sources tab.
• In the list of input methods on the left, scroll down and enable U.S., disable U.S. International.

This 'U.S. International' did all the evil. Some IDE use their own input system, while Eclipse uses common input. This feature is one of those 'little convenient things' (just like smart quotes) which turn my life on mac into nightmare sometimes.