When “” == s is false but “”.equals( s ) is true

Question

EDIT Thanks for the prompt responses. Please see what the real question is. I have made it bold this time.

I do understand the difference between ==

Answer 1

As I understand it while compiling the Java code to bytecode or while running the program same strings will be referenced to the same object in the most cases to save memory. So sometimes you get away with == comparisons of strings. But this is a compiler optimization you can not rely on.

But then sometimes it happens that the compiler decides to not do this optimization or there is no way for the program to see that the strings are the same and out of the sudden the check fails since you are relying on some underlying optimization voodoo that depends on implementation of the jvm you are using and so on.

So using equals is always the good thing to do. For empty strings there are other possibilities like comparing with length == 0 or if you don't care about backwards compatibility there is string.empty().