Have System properties always values

Question

Do System.getProperty("line.separator") and System.getProperty("os.name") always have values?

Or do I need to check the return value in the code for null?

Answer 1

Yes, they are inserted automatically by the JVM

Answer 2

The question is: can your code handle a null? If yes check for it, even if it is extremely unrealistic that this part of the code will ever be called, if not add a if null -> terminate concept, if that might cause trouble otherwise.

While the JVM will insert this for you, there are still two cases left where you can get null:

• The JVM has a bug
• Someone in the background deletes these properties.

None of these cases is likely enough to require to handle them by default.