Question on String comparision?

[Kumar Raja]

Hi All,

I have seen codes where the way Strings are compared is different, which is illustrated below. I'm not sure which is a better approach.

For eg.

String str1="abc";

Now what is the difference between

"abc".equals(str1) and str1.equals("abc").

In either case, we are comparing two different objects. But which one is preferred over the other.

My lead was happy when I used "abc".equals(str1) but why? I was hesitant to ask him and may be there are some interesting things which everybody should know about this diff.

[Joanne Neal]

The first one avoids the possibility of a NullPointerException if str1 is null.
With the second one you should always check for null first

if ((str1 != null) && str1.equals("abc")) {
}

[Kumar Raja]

Ah right....

I should have done a minimal research on this