To ensure that the code that you write is always clean and complaint to your project specific coding standards and guidelines, it is important that you configure your eclipse to effectively use its compiler settings, Formatter, CheckStyle and related built in features. Most developers wouldn't bother to do so but trust me that it is huge time saver in long run and shall always keep your code quality under check.
Following spread sheet has the configuration that we use in our current projects. You can customize these settings according to your development standards and needs.
Also ideally your Eclipse should be configured with your "code formatter" and "CheckStyle" XML configurations. To start with you can simply import these xmls that are attached to this page to enable code formatting and checkstyle for your code. You can get more detail on CheckStyle at http://checkstyle.sourceforge.net/.
Links to configure the CheckStyle, Formatter and compiler setting can be found under your Eclipse-->Preferences menu.