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
String oldValue= setValue(data.getKey(), newValue);
		validateSettings(data.getKey(), oldValue, newValue);
	}
	
	protected void textChanged(Text textControl) {
		Key key= (Key) textControl.getData();
		String number= textControl.getText();
		String oldValue= setValue(key, number);
		validateSettings(key, oldValue, number);
	}	
	protected boolean checkValue(Key key, String value) {
		return value.equals(getValue(key));
	}
	
	protected String getValue(Key key) {
		return key.getStoredValue(fLookupOrder, false, fManager);
	}
	
	protected boolean getBooleanValue(Key key) {
		return Boolean.valueOf(getValue(key)).booleanValue();
	}
	
	protected String setValue(Key key, String value) {
		String oldValue= getValue(key);
		key.setStoredValue(fLookupOrder[0], value, fManager);
		return oldValue;
	}
	
	protected String setValue(Key key, boolean value) {
		return setValue(key, String.valueOf(value));