How "Pattern.matches(regex, input)" function works?

Pattern.matches(regex, input);
matches function do this:
"Compiles the given regular expression and attempts to match the given input against it.".

I cant understand the above statement.
can u explain me how the above function works and for what purpose it will be used?

It's really useful, I use it a lot. You can use it to search Strings for the regex you specify. Can be used for... something that checks if an email is valid for example, or to strip html (remove everything between <> and &; or something. ;))

Have a look at this. :)

OP: Do you know what a regular expression is? If not have a read of Regular Expressions in Sun's Tutorial.