What version tomcat?
On Mon, Aug 30, 2010 at 3:38 PM, Steffen Heil <li...@steffen-heil.de> wrote:
> Hi
>
> I am sorry, I am asking something not really related to tomcat here.
> While this may sound like a beginners question, I think I really what I am
> doing in java, but this time I suspect I have found a scenario where the
> sun/oracle VM exposes a bug with pure String handling.
>
> So anyone who can find a bug in the procedure posted below is very welcome.
> So is everyone who can direct me to some place better suited to ask this
> question.
>
> Finding bugs in a static method that only takes immutable arguments usually
> seems easy... Turns out, it is not.
>
> However, please note that I already tried to debug this in various ways and
> the exception does NOT occur, as soon as a debugger is attached. The
> exception is only thrown under 64bit Linux Server-VM, within tomcat. It is
> neither thrown under 64bit Windows, nor on the very same Linux VM as
> standalone testcase, nor when a debugger is remotely attached. The JREs
> testest are 1.6u20 and 1.6u21.
>
> The code in question is the following:
>
>
> @SuppressWarnings( "null" )
> public final static String replaceAll( String stack, String ...
> replacements )
> {
> try {
> if ( stack == null )
> return stack;
> int index, pos;
> String niddle = null, string;
> int niddleLength, stringLength;
> for ( index = 0; true; index += 2 ) {
> if ( index >= replacements.length )
> return stack;
> niddle = replacements[ index ];
> pos = stack.indexOf( niddle );
> if ( pos != - 1 )
> break;
> }
> StringBuilder buffer = new StringBuilder( stack );
> niddleLength = niddle.length();
> string = replacements[ index + 1 ];
> if ( string == null )
> do
> buffer.delete( pos, pos +
> niddleLength );
> while ( ( pos = buffer.indexOf( niddle, pos
> ) ) != - 1 );
> else {
> stringLength = string.length();
> do {
> /*331*/ buffer.replace( pos, pos + niddleLength,
> string );
> pos += stringLength;
> } while ( ( pos = buffer.indexOf( niddle,
> pos ) ) != - 1 );
> }
> index += 2;
> for ( ; index < replacements.length; index += 2 ) {
> niddle = replacements[ index ];
> string = replacements[ index + 1 ];
> niddleLength = niddle.length();
> if ( string == null )
> for ( pos = 0; ( pos =
> buffer.indexOf( niddle, pos ) ) != - 1; )
> buffer.delete( pos, pos +
> niddleLength );
> else {
> stringLength = string.length();
> for ( pos = 0; ( pos =
> buffer.indexOf( niddle, pos ) ) != - 1; pos += stringLength )
> buffer.replace( pos, pos +
> niddleLength, string );
> }
> }
> return buffer.toString();
> } catch ( Throwable t ) {
> .... (code to dump the arguments and the stack trace) ...
> }
> }
>
>
> Note, that when the method is called, there are two arguments: one String
> and a String[] with a length of 1004 Strings.... (I guarantee that this
> String array is NOT modified during execution, not even afterwards.)
> The execption is (it is thrown indirectly in the marked line 331):
>
> java.lang.StringIndexOutOfBoundsException: start > length()
> at
> java.lang.AbstractStringBuilder.replace(AbstractStringBuilder.java:799)
> at java.lang.StringBuilder.replace(StringBuilder.java:271)
> at
> com.osiris4.core.utils.StringUtils.replaceAll(StringUtils.java:331)
> ....
>
>
> I can provide real arguments that lead to this exception, however, as there
> are more than 1000 Strings (partially large ones) involved, I will skip
> them
> here.
> Anyone interested will get them by mail. I have various samples.
>
>
> Currently this prevents loading my web application in about one of three
> times. (And it also happens during internal computations which prevents
> further work.) Sometimes this error can be "reproduced" (by restarting
> tomcat) 10 times in a row, sometimes it does not occur within 20 restarts
> at
> all. (Without changing anything in the systems configuration.)
>
>
> Sorry again, for asking off-topic, but I don't know where to ask for help
> anymore.
>
> Regards,
> Steffen
>
>
