null comparison

Question

This might sound like a real dumb question but please bear with me :) so I have a if condition in my code like if ((msgBO.getEmpId().equals("") == false )) { // do something } My question is, if I make the above statement as msgBO.getEmpId().equals(null) == false would it make any difference or this way I am trying to compare two different things?

Answer 1

Yes, there is a big difference between "" (the empty String) and null (no String at all).

Any Object reference can point to null. That represents 'no data' or 'nothing.' The empty string "" represents a String with no length.

An example of this is the following:

String one = null;
String two = "";
int oneLength = one.length();
int twoLength = two.length();

The first call to length will throw a NullPointerException. And the second will return 0.