Question

In Java, what is the difference between “” (empty quotes) and ” ” (quotes with a single space) and how do I test the former in terms of a char?

Answer 1

"" represents the empty string. " " is not empty, it contains a single space character.

You can’t test the former in terms of a char, as there are no characters: test for it in terms of a String: it is the String of length zero, and String.equals("") returns true for the empty string.

Or in terms of char arrays, the empty string corresponds to the char array of length zero, e.g.:

char noChars[] = new char[0];
String str = new String(noChars);
// now str is the empty String