I want to compare 2 or more (if posible) .properties files, exactly are i18n files. So I have the default messages_es.properties where I first add the keys with values, what I really need is to compare only the keys of the default/primary messages_es.properties with other .properties file for example messages_en.properties, to know which translations are left on different .properties files.
Basically:
The O/P should show the keys missing on the 2nd .properties files.
Class Properties has methods
public synchronized void load(InputStream inStream)
public synchronized void load(Reader reader)
You can use them to load your files.
Then use method
public Set<String> stringPropertyNames()
To get set of properties.
Finally Set has methods
boolean retainAll(Collection<?> c)
boolean removeAll(Collection<?> c)
To work with difference.