StackOverflow Exception with Regexes

[masterrs.mind]

Hi All,

I am using Regular Expressions in order to replace and strip certain html tags from the body of html.
I am using a properties file with key value pairs for the Regex patterns
I am encountering the following errors when each time the Regular Expression has been executed.

Exception in thread "main" java.lang.StackOverflowError
at java.util.regex.Pattern$LazyLoop.match(Unknown Source)
at java.util.regex.Pattern$GroupTail.match(Unknown Source)
at java.util.regex.Pattern$BranchConn.match(Unknown Source)
at java.util.regex.Pattern$CharProperty.match(Unknown Source)
at java.util.regex.Pattern$Branch.match(Unknown Source)
at java.util.regex.Pattern$GroupHead.match(Unknown Source)

Here are the properties.
0 T:\\(.*?\\): :
1 R:<P>&nbsp;</P>: :
2 R:&nbsp;: :
3 R:<SPAN(.|\n)*?>: :
4 R:</SPAN>: :
5 R:<TD(.|\n)*?>:<td>:
6 R:<P><IMG(.|\n)*?></P>:<hr/>:
7 C:StrongPattern:<P>(.|\n)*?<STRONG>(.|\n)*?/P>:<h1>:</h1>:<h2>:</h2>:
8 C:NestedTablePattern?s)<td>(.*?)</td>:<h1>:</h1>:
9 R:<p><br/>[\\r\\n]+<h1>:<h1>:
10 R:</h1></p>:</h1>:
11 R:<P><IMG(.|\n)*?>:<hr/>:

Is it something wrong with my Regexes?How can I possibly eliminate the errors.

Thank in advance.

[Eranga]

StackOverflowError means that you have infinite recursion thing happening in your code. Did you check anything for that in your code?

Is that the complete error message you comes with?

[masterrs.mind]

Hi,
yeah I got it resolved,I changed my regex definition and now it is working fine.
Yes that is due to infinite recursion.

Thanks

[Steve11235]

It may not be infinite, but just too much. Regex can do crazy things, even if they are valid.

[neilcoffey]

Maybe you could post the changes you made?

[masterrs.mind]

Actually I was getting the error when running transformations for IMG tag and <P><STRONG> patterns,because i don't need to check for next lines in those cases(previously they were <P><IMG(.|\n)*?></P>)

All I have done is removing |(or) from Regexps.
So my Regexps turned out to be

6 R:<P><IMG(.)*?></P>:<HR/>:
7 R:<IMG(.)*?>: :
8 C:StrongPattern:<P>(.)*?<STRONG>(.)*?/P>:<H1>:</H1>:<H2>:</H2>:

That solved my problem.
Hope this will be helpful for someone.

[neilcoffey]

In general, it may well be more efficient to use character classes [] instead of the pipe where you can achieve the equivalent. So you could write:

<P><IMG[.\n]*?></P>:<hr/>

You can also set the DOT_ALL flag when you compile the pattern instead of putting both dot and newline (unless you really want to include, say, \n but not \r, I guess).

I personally think it's a bit odd to have a capturing group modified by a star (....)* (perhaps you meant a non-capturing group (?:.....)*.