File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Beginning Java and the fly likes Validating empty string Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Beginning Java
Bookmark "Validating empty string" Watch "Validating empty string" New topic

Validating empty string

Nico Yukiko

Joined: Aug 24, 2005
Posts: 21
i wrote if (email==""){
but it does not show this is i leave emai as empty???
Mark Spritzler

Joined: Feb 05, 2001
Posts: 17276

You should always compare Strings using the equals method. == will not always return true.


Perfect World Programming, LLC - iOS Apps
How to Ask Questions the Smart Way FAQ
Michael Ernest
High Plains Drifter

Joined: Oct 25, 2000
Posts: 7292

The == operator here tests whether "" and email point are in the same memory location. Even if the variable email did in fact contain an empty string, the == doesn't know that's what you mean. The equals() method in the String class is a test for what's in the String, rather than where the thing is located.

Make visible what, without you, might perhaps never have been seen.
- Robert Bresson
Stephen Boston
Ranch Hand

Joined: Jul 14, 2005
Posts: 165
Comparing Strings was difficult for me as well. I think this is what you are looking for.

[ September 13, 2005: Message edited by: Stephen Boston ]

Steve<br /> <br />No matter where you go, there you are.<br /> <br />"My evil self is at the door, and I have no power to stop it."
I agree. Here's the link:
subject: Validating empty string
It's not a secret anymore!