Bug 23320 Incomplete classpath and circular classpath options should be surfaced
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/CompilerPreferencePage.java
if ((VERSION_1_3.equals(complianceLevel)
				&& checkValue(PREF_PB_ASSERT_AS_IDENTIFIER, IGNORE)
				&& checkValue(PREF_SOURCE_COMPATIBILITY, VERSION_1_3)
				&& checkValue(PREF_CODEGEN_TARGET_PLATFORM, VERSION_1_1))
			|| (VERSION_1_4.equals(complianceLevel)
				&& checkValue(PREF_PB_ASSERT_AS_IDENTIFIER, ERROR)
				&& checkValue(PREF_SOURCE_COMPATIBILITY, VERSION_1_4)
				&& checkValue(PREF_CODEGEN_TARGET_PLATFORM, VERSION_1_4))) {
			return DEFAULT;
		}
		return USER;
	}
	
	/*
	 * @see IPreferencePage#performOk()
	 */
	public boolean performOk() {
		String[] allKeys= getAllKeys();
		
		
		Hashtable actualOptions= JavaCore.getOptions();
		
		boolean hasChanges= false;
		for (int i= 0; i < allKeys.length; i++) {
			String key= allKeys[i];
			String val=  (String) fWorkingValues.get(key);
			String oldVal= (String) actualOptions.get(key);
			hasChanges= hasChanges | !val.equals(oldVal);
			
			actualOptions.put(key, val);