Bug 94367 cannot clear compiler compliance setting at the project level
i200505092010 Cannot disable the Java compiler project-specific preferences for some projects. Steps to reproduce: 1 - check out from CVS a Java project that has project-specific Java compiler settings enabled (example: org.eclipse.core.runtime). 2 - open the properties dialog for the project, select the Java compiler node, disable project-specific Java compiler preferences. 3 - Commit the changes by pressing "Ok" and reopen the properties dialog. It looks like the settings were not saved (project-specific settings are still enabled).
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/OptionsConfigurationBlock.java
protected final static Key getJDTCoreKey(String key) {
		return getKey(JavaCore.PLUGIN_ID, key);
	}
	
	protected final static Key getJDTUIKey(String key) {
		return getKey(JavaUI.ID_PLUGIN, key);
	}
	
		
	private void testIfOptionsComplete(Key[] allKeys) {
		for (int i= 0; i < allKeys.length; i++) {
			if (allKeys[i].getStoredValue(fLookupOrder, false, fManager) == null) {
				JavaPlugin.logErrorMessage("preference option missing: " + allKeys[i] + " (" + this.getClass().getName() +')');  
			}
		}
	}
	
	protected void settingsUpdated() {
	}
	
	
	/*protected Map getDefaultOptions() {
		Map workingValues= new HashMap();
		DefaultScope defaultScope= new DefaultScope();
		for (int i= 0; i < fAllKeys.length; i++) {
			Key curr= fAllKeys[i];
			workingValues.put(curr, curr.getStoredValue(defaultScope, fManager));
		}
		return workingValues;