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Empty string

Amrita Dole

Joined: Nov 12, 2003
Posts: 20
How do you check whether a string is empty or not in Java?
Eg. string-
String str = "hello";
Ernest Friedman-Hill
author and iconoclast

Joined: Jul 08, 2003
Posts: 24199

Welcome to JavaRanch!
There are two different kinds of "empty" you might be talking about. One is zero-length; i.e., the String might be "" . The best way to test for this is to use the length() method -- i.e.,
if (s.length() == 0) ...
The other definition is that there's no String object at all -- s might be null, like a null pointer in C. The test for this looks like
if (s == null) ...

If this is possible, then be sure to test for null before calling any methods on the String; if you don't you'll get an exception.
if (s != null && s.length() > 0) ...
I'm going to have this thread moved to "Java in General -- Beginner" where it's on-topic.

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subject: Empty string
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