<extension point="org.eclipse.core.runtime.preferences">
	<initializer 
	    class="my.package.ProjectPreferenceInitializer" 
	    id="my.package.projectPreferenceInitializer"/>
	<modifier 
		class="my.package.ProjectPreferenceModifier" 
		id="my.package.projectPreferenceMofidier" 
		name="Your Preference Modifier"/>
</extension>

public class ProjectPreferenceModifier implements IPreferenceChangeListener {
	
    @Override
    public void preferenceChange(PreferenceChangeEvent event) {
    	System.out.println("");
    }
}