Look at my code again...
if (null == s || s.length() == 0) ...
Java translates x == y into x.equals(y). If I had said
if (s == null)
and s was null, you would get a null pointer exception. However, the
constant null is handled specially -- it has an equals method that always
works. Thus, saying
if (null == s)
will not fail with a null pointer exception.
I also used the short-circuiting "or" operator || to connect the two pieces.
In effect, a || b means "if a evaluates to false, evaluate b."
In a case like this, || often leads to cleaner and more efficient code than
nesting "if" statements.
By the way, you could also say:
if (null != s && s.length() != 0)
which would yield the same result as Mark'code below.
...Richard
-----Original Message-----
From: Mark Foley [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, January 05, 2000 4:22 PM
To: [EMAIL PROTECTED]
Subject: Re: [SERVLET-INTEREST] Checking for null
Hi,
Wouldn't your conditional statement cause a null pointer exception if s is
null? Try it!
I do this:
...
if(null != s) {
if(s.length() != 0) {
// it's not null and it's not empty
}
}
Regards,
Mark
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