Hi all. I`ve recently being developing a custom taglibrary for my company. In doing so I have uncovered some problems with Jasper in version 3.1 during my test. Now we are supporting Regular expressions as extensions to our tags like this excerpt from our jsp page: <dbp:attribute name="format" value="\\s*(\\w)\\w+\\s+(\\w)\\w+"/> Now this however gives a huge hickup in Jasper as it gives the following output: org.apache.jasper.JasperException: Unable to compile class for JSPwork\localhost_8080%2Fdbp\_0002fexample_0002edbpexample_0002edbp_jsp_0.ja va:213: Invalid escape character. JspRuntimeLibrary.introspecthelper(_jspx_th_dbp_attribute_4,"value","s\*\(w\ )w+s+\(w\)w+",null,null,false); Now this regular expression is not only wrong it`s totally mangled from: "\\s*(\\w)\\w+\\s+(\\w)\\w+" to: "s\*\(w\)w+s+\(w\)w+" Jasper also does this with {0}{1} and turns it into \{1\}\{2\} on the same page. Now this works on Resin without any hickup or problems, so what is wrong. I have looked a little at the source code and discovered the Jasper in the JspReader class used strips the \\ character from any value ( in the parseToken(true) method ) . This is IMHO wrong and stops me from seriously using or testing this functionality on Tomcat (which by the way works for all my other tests only this has me stomped). Now what makes it add those strange \\ characters (evaluated to \ on output) I haven`t been able to exactly trace yet, but I am still looking. Please somebody help so my project can be absolutely sure it isn`t our fault. Mikael Helbo Kjær Software Developer @ DIA a/s